-stream: IETF -area: Internet -status: informational -author: Leon van Kammen -date: 2023-04-12T00:00:00Z -workgroup: Internet Engineering Task Force -value: draft-XRFRAGMENTS-leonvankammen-00 -- - - -
-- -Version: 0.5
-
An open specification for hyperlinking & deeplinking 3D fileformats.
-This draft is a specification for interactive URI-controllable 3D files, enabling hypermediatic navigation, to enable a spatial web for hypermedia browsers with- or without a network-connection.
-XR Fragments allows us to better use implicit metadata inside 3D scene(files), by mapping it to proven technologies like URI Fragments.
--Almost every idea in this document is demonstrated at https://xrfragment.org
-
- -
How can we add more control to existing text and 3D scenes, without introducing new dataformats?
-Historically, there’s many attempts to create the ultimate 3D fileformat.
-The lowest common denominator is: designers describing/tagging/naming things using plain text.
-XR Fragments exploits the fact that all 3D models already contain such metadata:
XR Fragments allows deeplinking of 3D objects by mapping objectnames to URI fragments
- -- -
XR Fragments utilizes URLs:
- -href metadata inside 3D scene-files to enable interactionsIt solves:
- --- -NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible
-
XR Fragments views XR experiences through the lens of 3D deeplinked URI’s, rather than thru code(frameworks) or protocol-specific browsers (webbrowser e.g.).
-To aid adoption, the standard comprises of various (optional) support-levels, which incorporate existing standards like W3C Media Fragments and URI Templates (RFC6570) to promote spatial addressibility, sharing, navigation, filtering and databinding objects for (XR) Browsers.
-- -XR Fragments is in a sense, a heuristical 3D format or meta-format, which leverages heuristic rules derived from any 3D scene or well-established 3D file formats, to extract meaningful features from scene hierarchies.
-
-These heuristics, enable features that are both meaningful and consistent across different scene representations, allowing higher interop between fileformats, 3D editors, viewers and game-engines.
for XR Browsers)
- -href metadata traditionally implies click AND navigate, however XR Fragments adds stateless click (xrf://....) via the xrf:// scheme, which does not change the top-level URL-adress (of the browser).
-This allows for many extra interactions via URLs, which otherwise needs a scripting language.
-These are called hashbus-only events/
-- -Being able to use the same URI Fragment DSL for navigation (
-href: #foo) as well as interactions (href: xrf://#foo) greatly simplifies implementation, increases HFL, and reduces need for scripting languages.
This opens up the following benefits for traditional & future webbrowsers:
- -xrf:// hashbus (xrf://#person=walk to trigger walk-animation for object person)XR Fragments itself are hypermediatic and HTML-agnostic, though pseudo-XR Fragment browsers can be implemented on top of HTML/Javascript.
- -| principle | -3D URL | -HTML 2D URL | -
|---|---|---|
| the XRWG | -wordgraph (collapses 3D scene to tags) | -Ctrl-F (find) | -
| the hashbus | -hashtags alter camera/scene/object-projections | -hashtags alter document positions | -
| src metadata | -renders content and offers sourceportation | -renders content | -
| href metadata | -teleports to other XR document | -jumps to other HTML document | -
| href metadata | -triggers predefined view | -Media fragments | -
| href metadata | -triggers camera/scene/object/projections | -n/a | -
| href metadata | -draws visible connection(s) for XRWG ‘tag’ | -n/a | -
| href metadata | -filters certain (in)visible objects | -n/a | -
| href metadata | -href=“xrf://#-foo&bar” | -href=“javascript:hideFooAndShowBar()` | -
| - | (this does not update topLevel URI) | -(this is non-standard, non-hypermediatic) | -
-- -An important aspect of HFL is that URI Fragments can be triggered without updating the top-level URI (default href-behaviour) thru their own ‘bus’ (
-xrf://#.....). This decoupling between navigation and interaction prevents non-standard things like (href:javascript:dosomething()).
- -
See appendix below in case certain terms are not clear.
- -- -
For typical HTTP-like browsers/applications:
- -reserved = gen-delims / sub-delims
-gen-delims = "#" / "&"
-sub-delims = "," / "="
--- -Example:
-://foo.com/my3d.gltf#room1&prio=-5&t=0,100
| Demo | -Explanation | -
|---|---|
room1 |
-vector/coordinate argument e.g. | -
room1&cam1 |
-combinators | -
-- -this is already implemented in all browsers
-
Pseudo (non-native) browser-implementations (supporting XR Fragments using HTML+JS e.g.) can use the ? search-operator to address outbound content.
-In other words, the URL updates to: https://me.com?https://me.com/other.glb when navigating to https://me.com/other.glb from inside a https://me.com WebXR experience e.g.
-That way, if the link gets shared, the XR Fragments implementation at https://me.com can load the latter (and still indicates which XR Fragments entrypoint-experience/client was used).
- -
3D files contain an hierarchy of objects.
-XR Fragments assumes the following objectname-to-URI-Fragment mapping, in order to deeplink 3D objects:
- my.io/scene.fbx
- +─────────────────────────────+
- │ sky │ src: http://my.io/scene.fbx#sky (includes building,mainobject,floor)
- │ +─────────────────────────+ │
- │ │ building │ │ src: http://my.io/scene.fbx#building (includes mainobject,floor)
- │ │ +─────────────────────+ │ │
- │ │ │ mainobject │ │ │ src: http://my.io/scene.fbx#mainobject (includes floor)
- │ │ │ +─────────────────+ │ │ │
- │ │ │ │ floor │ │ │ │ src: http://my.io/scene.fbx#floor (just floor object)
- │ │ │ │ │ │ │ │
- │ │ │ +─────────────────+ │ │ │
- │ │ +─────────────────────+ │ │
- │ +─────────────────────────+ │
- +─────────────────────────────+
-
--- -Every 3D fileformat supports named 3D object, and this name allows URLs (fragments) to reference them (and their children objects).
-
Clever nested design of 3D scenes allow great ways for re-using content, and/or previewing scenes.
-For example, to render a portal with a preview-version of the scene, create an 3D object with:
https://scene.fbx-- -It also allows sourceportation, which basically means the enduser can teleport to the original XR Document of an
-srcembedded object, and see a visible connection to the particular embedded object. Basically an embedded link becoming an outbound link by activating it.
-
- -Compatible 3D fileformats: glTF, usdz, obj, collada, THREE.json, X3D e.g.
-
A 3D scene-file can be considered XR Fragment-compatible when it contains metadata: -1. implicit: there’s at least one object with a name (*) -2. explicit: (optional) object(s) have (level2) href extras.
- --- -* = last wins in case of non-unique names
-
There are optional auto-loaded side-car files to enable hasslefree XR Movies.
-they can accomodate developers or applications who (for whatever reason) must not modify the 3D scene-file (a .glb e.g.).
scene.glb <--- 'href' extra [heuristic] detected inside!
-scene.png (preview thumbnail)
-scene.ogg (soundtrack to plays when global 3D animation starts)
-scene.vtt (subtitles for accessibility or screenreaders)
-scene.json (sidecar JSON-file with explicit metadata)
-heuristics:
- -href custom property/extra is found in a 3D scenescene.xrf.glb <--- '.xrf.' sidecar file heuristic detected!
-scene.xrf.png (preview thumbnail)
-scene.xrf.ogg (soundtrack to plays when global 3D animation starts)
-scene.xrf.vtt (subtitles for accessibility or screenreaders)
-scene.xrf.json (sidecar JSON-file with explicit metadata)
--- -A fallback-mechanism to turn 3D files into XR Movies without editing them.
-
heuristics:
- -.xrf. should be present in the filename (scene.xrf.glb e.g.)More secure protocols (Nextgraph e.g.) don’t allow for simply polling files. -In such case, subdocuments or extended attributes should be polled:
- --- -NOTE: in the examples below we use the href-heuristic, but also the
-.xrf.chained-extension applies here.
myspreadsheet.ods
-└── explainer.glb <--- 'href' extra [heuristic] detected inside!
- ├── explainer.ogg (soundtrack to play when global 3D animation starts)
- ├── explainer.png (preview thumnbnail)
- ├── explainer.json (sidecar JSON-file with explicit metadata)
- └── explainer.vtt (subtitles for accessibility or screenreaders)
-If only extended attributes (xattr) are available, the respective referenced file can be embedded:
- -$ setfattr -n explainer.ogg -v "soundtrack.ogg" explainer.glb
-$ setfattr -n explainer.png -v "thumbnail.png" explainer.glb
-$ setfattr -n explainer.vtt -v "subtitles.vtt" explainer.glb
--- -NOTE: Linux’s
-setfattr/getfattrisxattron mac, andSet-Content/Get-contenton Windows. See pxattr for lowlevel access.
For developers, sidecar-file can allow for defining explicit XR Fragments links (>level1), outside of the 3D file.
-This can be done via (objectname/metadata) key/value-pairs in a JSON sidecar-file:
<----{
- "aria-description": "description of scene",
- "button": {
- "href": "#roomB",
- "aria-description": "description of room"
- }
-}
--- -This will make object
-buttonclickable, and teleport the user to objectroomB.
So after loading experience.glb the existence of experience.json is detected, to apply the explicit metadata.
-The sidecar will define (or override already existing) extras, which can be handy for multi-user platforms (offer 3D scene customization/personalization to users).
-- -In THREE.js-code this would boil down to:
-
scene.userData['aria-description'] = "description of scene"
- scene.getObjectByName("button").userData.href = "#roomB"
-
- // now the XR Fragments parser can process the XR Fragments userData 'extras' in the scene
-- -
-- -XR Fragments allows deeplinking of 3D objects by mapping objectnames to URI fragments
-
XR Fragments tries to seek to connect the world of text (semantical web / RDF), and the world of pixels.
-Instead of forcing authors to combine 3D/2D objects programmatically (publishing thru a game-editor e.g.), XR Fragments integrates all which allows a universal viewing experience.
+───────────────────────────────────────────────────────────────────────────────────────────────+
- │ │
- │ U R N │
- │ U R L | │
- │ | |-----------------+--------| │
- │ +--------------------------------------------------| │
- │ | │
- │ + https://foo.com/some/foo/scene.glb#someview <-- http URI (=URL and has URN) │
- │ | │
- │ + ipfs://cfe0987ec9r9098ecr/cats.fbx#someview <-- an IPFS URI (=URL and has URN) │
- │ │
- │ ec09f7e9cf8e7f09c8e7f98e79c09ef89e000efece8f7ecfe9fe <-- an interpeer URI │
- │ │
- │ │
- │ |------------------------+-------------------------| │
- │ | │
- │ U R I │
- │ │
- +───────────────────────────────────────────────────────────────────────────────────────────────+
-
-Fact: our typical browser URL’s are just a possible implementation of URI’s (for untapped humancentric potential of URI’s see interpeer.io or NextGraph )
- --- -XR Fragments does not look at XR (or the web) thru the lens of HTML or URLs.
-
But approaches things from a higherlevel local-first 3D hypermedia browser-perspective.
Below you can see how this translates back into good-old URLs:
- - +───────────────────────────────────────────────────────────────────────────────────────────────+
- │ │
- │ the soul of any URL: ://macro /meso ?micro #nano │
- │ │
- │ 2D URL: ://library.com /document ?search #chapter │
- │ xrf:// │
- │ 4D URL: ://park.com /4Dscene.fbx ─> ?other.glb ─> #object ─> hashbus │
- │ │ #filter │ │
- │ │ #tag │ │
- │ │ (hypermediatic) #material │ │
- │ │ ( feedback ) #animation │ │
- │ │ ( loop ) #texture │ │
- │ │ #variable │ │
- │ │ │ │
- │ XRWG <─────────────────────<─────────────+ │
- │ │ │ │
- │ └─ objects ──────────────>─────────────+ │
- │ │
- │ │
- +───────────────────────────────────────────────────────────────────────────────────────────────+
-
--- -?-linked and #-linked navigation are JUST one possible way to implement XR Fragments: the essential goal is to allow a Hypermediatic FeedbackLoop (HFL) between external and internal 4D navigation.
-
| fragment | -type | -example | -info | -
|---|---|---|---|
#...... |
-vector3 | -#room1 #room2 #cam2 |
-positions/parents camera(rig) (or XR floor) to xyz-coord/object/camera and upvector | -
| Media Fragments | -media fragment | -#t=0,2&loop |
-play (and loop) 3D animation from 0 seconds till 2 seconds | -
These are the possible ‘extras’ for 3D nodes and sidecar-files
- -| key | -type | -example (JSON) | -function | -existing compatibility | -
|---|---|---|---|---|
href |
-string | -"href": "b.gltf" |
-XR teleport | -custom property in 3D fileformats | -
- -
Explicit href metadata (‘extras’) in a 3D object (of a 3D file), hint the viewer that the user “can interact” with that object :
- -| fragment | type | example value |
-|href| string (uri or predefined view) | #pyramid#lastvisitxrf://#-someobject://somefile.gltf#foo
|
When clicking an “href”-value, the user(camera) is teleport to the referenced object.
- -The imported/teleported destination can be another object in the same scene-file, or a different file.
- -| spec | action | feature |
-|-|-|-|
-| level0+1 | hover 3D file href | show the preview PNG thumbnail (if any). |
-| level0+1 | launch 3D file href | replace the current scene with a new 3D file (href: other.glb e.g.) |
-| level2 | click internal 3D file href (#roomB e.g.) | teleport the camera to the origin of object(name roomB). See [[teleport camera]].|
-| level2 | click external 3D file href (foo.glb e.g.) | replace the current scene with a new 3D file (href: other.glb e.g.) |
-| level2 | hover external 3D file href | show the preview PNG thumbnail (if any sidecar, see level0) |
-| level2 | click href | hashbus: execute without changing the toplevel URL location (href: xrf://#someObjectName e.g.) |
-| level3 | click href | set the global 3D animation timeline to its Media Fragment value (#t=2,3 e.g.) |
-- -NOTE: hashbus links (
-xrf://#foo&bar) don’t change the toplevel URL, which makes it ideal for interactions (in contrast to typical#roomCnavigation, which benefit back/forward browser-buttons), see hashbus for more info.
- -
-- -these allow for XR Movies with a controllable timeline using
-hrefURI’s with Media Fragments
Just like with 2D media-files, W3C mediafragments (#t=1,2) can be used to control a timeline via the #t primitive.
-XR Fragments Level3 makes the 3D timeline, as well as URL-referenced files controllable via Media Fragments like:
href: #t=4 e.g. to control 3D timeline)xrf: URI scheme:
-
-href: xrf:foo.wav#t=0 to play a wavhref: xrf:news.glb?clone#t=0 to instance and play another experiencecontrols the animation(s) of the scene (or src resource which contains a timeline)
| fragment | type | functionality | -| #t=start,stop | [vector2] | start,stop (in seconds |
- -| Example Value | Explanation |
-| #t=1 | play (3D) animations from 1 seconds till end (and stop) |
-| #t=1,100 | play (3D) animations from 1 till 100 seconds (and stop) |
This compensates a missing element from Media Fragments to enable/disable temporal looping. .
- -| fragment | type | functionality | -| #loop | string | enables animation/video/audio loop | -| #-loop | string | disables animation/video/audio loop |
- -use [[URI Templates]] to control embedded media, for example a simple video-player:
- - foo.usdz
- │
- ├── ◻ loopbutton_enable
- │ └ href: #loop <-- enable global loop
- │
- ├── ◻ loopbutton_enable
- │ └ href: #-loop <-- disable global loop
- │
- ├── ◻ playbutton
- │ └ href: #t=10&loop <-- play global 3D timeline (all anims) (looped)
- │
- └── ◻ playbutton_external
- └ href: https://my.org/animation.glb#!&t=3,10 <-- import & play external anim
-
-- -
Prefixing objectnames with the following simple operators allow for extremely powerful XR interactions:
- --- -Examples:
-#+menuto show a object,#-menuto hide a menu,#!menuto teleport a menu,#*blockto clone a grabbable block,#|objectto share an object
Prefixing an object with an exclamation-symbol, will teleport a (local or remote) referenced object from/to its original/usercamera location.
[img[objecteleport.png]]
- -Usecases: -* show/hide objects/buttons (menu e.g.) in front of user -* embed remote (object within) 3D file via remote URL -* instance an interactive object near the user regardless of location -* instance HUD or semi-transparent-textured-sphere (LUT) around the user
- -Clicking the href-value above will:
- -#+ is always implied (objects are always made visible)This tiny but powerful symbol allows incredible interactive possibilities, by carefully positioning re-usable objects outside of a scene (below the usercamera’s floor e.g.).
- -#whiteroom&!explainer&!exitmenu-- -This will teleport the user to
-whiteroomand moves objectexplainerandexitmenuin front of the user.
Clicking the href-value above will:
- -foo.glb from my.org’s webserver#! indicates object teleport)https://foo.glb#roomB&!barClicking the href-value above will:
- -foo.glbfoo.glbxrf: was not used)-- -NOTE: level2 teleportation links, as well as instancing mitigates the ‘broken embedded image’-issue of HTML: always attaching the href-values to a 3D (preview) object (that way broken links will not break the design).
-
Example: clicking a 3D button with title ‘menu’ and href-value xrf:menu.glb?instance#t=4,5 would instance a 3D menu (menu.glb) in front of the user, and loop its animation between from 4-5 seconds (t=4,5)
-- -NOTE: combining instance-operators allows dynamic construction of 3D scenes (
-#london&!welcomeMenu&!fadeBoxe.g.)
The star-prefix will clone a (local or remote) referenced object to the usercamera’s location, and make it grabbable.
-Usecases:
-* object-picker (build stuff with objects)
-- -NOTE: this is basically the #! operator which infinitely clones the referenced object (instead of repositioning the object).
-
-- -How to show/hide/group material- or object- or animations by name?
-
Clicking href-values below will show/hide the targeted material- or animation or object-name (incl. children):
- -#-welcome#+welcome#-VR*https://foo.glb#bar&-welcomeMatching logic:
- --- -NOTE: to hide a skybox when importing/loading a 3D file (force AR) is possible by linking to `
-https://my.org/foo.glb#-skyboxorhttps://my.org/foo.glb#-skyboxmaterial
The pipe-symbol (|) sends a (targeted) object to the OS.
-Clicking the href-value below will:
-- -This URL can be fed straight into Web Share API or xdg-open
-
xrf://#|bar-- -NOTE: sharing is limited to (internal objects) via
-xrf:scheme-only
Prefixing the xrf: to href-values will prevent level2 href-values from changing the top-Level URL.
-- -Usecase: for non-shareable URLs like
-href: xrf:#t=4,5, to display a stateful msg e.g.).
Reason: XR Fragments is inspired by HTML’s href-attribute, which does various things:
- -The xrf: scheme will just do 2 & 3 (so the URL-values will not leak into the top-level URL).
-- -compliance with RFC 3986: unimplemented/unknown URI schemes (
-xrf:...e.g.) will not update the top-level URL
)
- -XR Fragments adopts Level1 URI Fragment expansion to provide safe interactivity.
-This is non-normative, and the draft spec is available on request.
- -
-- -Example URL:
-://foo/world.gltf#room1&t=10&cam
The URL-processing-flow for hypermedia browsers goes like this:
- -t) are present in the URL then (re)position the camera (to room1) and/or animation-range (10) accordingly.0,0,0 as camera coordinate (XR: add user-height) (example)cam assume that user(camera) positionEnd-users should always have read/write access to:
- -href navigates (and updates the URL) to another scene/file (and coordinate e.g. in case the URL contains XR Fragments).- -
navigation, portals & mutations
- -| fragment | -type | -example value | -
|---|---|---|
href |
-string (uri or predefined view) | -#room1#room1://somefile.gltf#room1 |
-
clicking an outbound “external”- or “file URI” fully replaces the current scene and assumes room2 by default (unless specified)
relocation/reorientation should happen locally for local URI’s (#....)
navigation should not happen “immediately” when user is more than 5 meter away from the portal/object containing the href (to prevent accidental navigation e.g.)
URL navigation should always be reflected in the client URL-bar (in case of javascript: see [here for an example navigator), and only update the URL-bar after the scene (default fragment #) has been loaded.
In immersive XR mode, the navigator back/forward-buttons should be always visible (using a wearable e.g., see [here for an example wearable)
make sure that the “back-button” of the “browser-history” always refers to the previous position (see [here)
ignore previous rule in special cases, like clicking an href using camera-portal collision (the back-button could cause a teleport-loop if the previous position is too close)
href-events should bubble upward the node-tree (from children to ancestors, so that ancestors can also conain an href), however only 1 href can be executed at the same time.
the end-user navigator back/forward buttons should repeat a back/forward action until a #... primitive is found (the stateless xrf:// href-values should not be pushed to the url-history)
» example implementation
-» example 3D asset
-» discussion
-- -By default position
-0,0,0of the 3D scene represents the walkable plane, however this is overridden when the following applies:
XR Fragment-compatible viewers can infer this data based scanning the scene for:
- -href and >0 faces)-- -optionally the viewer can offer thumbstick, mouse or joystick teleport-tools for non-roomscale VR/AR setups.
-
- -
Consider 3D scenes linking to eachother using these href values, attached to 3D button-objects:
href: schoolA.edu/projects.gltf#mathhref: schoolB.edu/projects.gltf#mathhref: university.edu/projects.gltf#mathThis would teleport users to the math-projects of those universities.
-Now consider adding a ‘webring index’-button to each file, with this href-value:
This would allow displaying the (remote 3D file) webring menu with various href-buttons inside, all centrally curated by the workgroup.
- -- -
XR Fragments does not aim to redefine the metadata-space or accessibility-space by introducing its own cataloging-metadata fields. -Instead, it encourages browsers to scan nodes for the following custom properties:
- -aria-*: .....)ARIA’s aria-description-metadata is normative, to aid accessibility and scene transcripts
-- -NOTE: please always start
-aria-descriptionwith a verb to aid transcripts.
The following metadata are non-normative but encouraged, since they are popular and cheap to parse:
- -og:*: .....)dc:*: .....){ and },-- -Example: object ‘tryceratops’ with
-aria-description: is a huge dinosaurus standing on a #mountaingenerates transcript#tryceratops is a huge dinosaurus standing on a #mountain, where the hashtags are clickable XR Fragments (activating the visible-links in the XR browser).
Individual nodes can be enriched with such metadata, but most importantly the scene node:
- -| metadata key | -example value | -
|---|---|
aria-description, og:description, dc:description |
-An immersive experience about Triceratops (*) |
-
SPDX |
-CC0-1.0 |
-
dc:creator |
-John Doe |
-
dc:title, og:title |
-‘Triceratops` (*) | -
og:site_name |
-https://xrfragment.org |
-
dc.publisher |
-NLNET |
-
dc.date |
-2024-01-01 |
-
dc.identifier |
-XRFRAGMENT-001 |
-
journal (bibTeX) |
-{Future Of Text Vol 3}, |
-
-- -* = these are interchangable (only one needs to be defined)
-
There’s no silver bullet when it comes to metadata, so XR Fragment-implementations should support where the metadata is/goes.
- --- -These attributes can be scanned and presented during an
-hreforsrceye/mouse-over.
- -
The addressibility of XR Fragments allows for unique 3D-to-text transcripts, as well as an textual interface to navigate 3D content.
-Spec:
aria-descriptions, and its narration (Screenreader e.g.) can be skipped (via 2-button navigation)back command should navigate back to the previous URL (alias for browser-backbutton)forward command should navigate back to the next URL (alias for browser-nextbutton)href with a #... XR fragment (which matches a 3d object name)go command should list all possible destinationsgo left command should move the camera around 0.3 meters to the leftgo right command should move the camera around 0.3 meters to the rightgo forward command should move the camera 0.3 meters forward (direction of current rotation).rotate left command should rotate the camera 0.3 to the leftrotate left command should rotate the camera 0.3 to the rightgo abc command should navigate to #scene2 in case there’s a 3D node with name abc and href value #scene2look command should give an (contextual) 3D-to-text transcript, by scanning the aria-description values of the current #... (3D object) value (including its children)do command should list all possible href values which don’t contain an #... XR Fragmentdo abc command should navigate/execute https://.../... in case a 3D node exist with name abc and href value https://.../...For specific user-profiles, gyroscope/mouse/keyboard/audio/visuals will not be available.
-Therefore a 2-button navigation-interface is the bare minimum interface:
Some 3D scene-fileformats have support for extensions.
-What if the functionality of those overlap?
-For example, GLTF has the OMI_LINK extension which might overlap with XR Fragment’s href:
-- -Priority Order and Precedence, otherwise fallback applies
-
1.Extensions Take Precedence: Since glTF-specific extensions are designed with the format’s -specific needs and optimizations in mind, they should take precedence over extras metadata -in cases where both contain overlapping functionality. -This approach aligns with the idea that extensions are more likely to be interpreted uniformly by glTF-compatible software.
- --- -Example 1 In case of the OMI_LINK glTF extension (
- -href: https://nlnet.nl) and an XR Fragment (href: #otherroomorhref: otherplanet.glb), it is clear thathttps://nlnet.nlshould open in a browsertab, whereas the XR Fragment links should teleport the user. If the OMI_LINK contains an XR Fragment (#room1e.g.) a teleport should be performed only (and other [overlapping] metadata should be ignored).Example 2 If an Extensions uses XR Fragments in URI’s (
-href: #otherroomorhref: xrf://-wallsin OMI_LINK e.g.), then perform them according to XR Fragment spec (teleport user). But only once: ignore further overlapping metadata for that usecase.
- -
Vendor-specific metadata in a 3D scenefiles, are similar to vendor-specific CSS-prefixes (-moz-opacity: 0.2 e.g.).
-This allows popular 3D engines/frameworks, to initialize specific features when loading a scene/object, in a progressive enhanced way.
Vendor Prefixes allows embedding 3D engines/framework-specific features a 3D file via metadata:
- -| what | -XR metadata | -Lowest common denominator | -
|---|---|---|
| CSS | -vendor-agnostic | -2D canvas + object referencing/styling | -
| XR Fragments | -vendor-agnostic | -3D camera + object(file) load/embed/click/referencing | -
| Vendor prefixs | -vendor-specific | -Specialized Entity-Component implementation | -
-- -Why? Because not all XR interactions can/should be solved/standardized by embedding XR Fragments into any 3D file. -The lowest common denominator between 3D engines is the ‘entity’-part of their entity-component-system (ECS). The ‘component’-part can be progressively enhanced via vendor prefixes.
-
For example, the following metadata can be added to a .glb file, to make an object grabbable in AFRAME:
- -+────────────────────────────────────────────────────────────────────────────────────────────────────────+
-│ http://y.io/z.glb | AFRAME app │
-│-----------------------------------------------+--------------------------------------------------------│
-│ | │
-│ | after loading the glb, john can be placed into the │
-│ +-[3D mesh]-+ | castle via hands, because the author added metadata to │
-│ | / \ | | john via either: │
-│ | / \ | | │
-│ | / \ | | 1. Blender (custom property-box, no plugins needed) │
-│ | |_____| | | │
-│ +-----│-----+ | 2. javascript-code: │
-│ │ | │
-│ ├─ name: castle | for( var com in this.el.components ){ │
-│ └─ tag: house baroque | this.el.object3D.userData[`-AFRAME-${com}`] = '' │
-│ | } │
-│ [3D mesh-+ | // save to z.glb in AFRAME inspector │
-│ | ├─ name: john | │
-│ | O ├─ age: 23 | │
-│ | /|\ ├─ -aframe-grabbable: '' | > inits 'grabbable' component on object john │
-│ | / \ ├─ -aframe-material.color: '#F0A' | > inits 'material' component on object john │
-│ | ├─ -aframe-text.value: '{name}{age}'| > inits 'text' component (*) with value 'john' │
-│ | ├─ -three-material.fog: false | > changes material settings in THREE.js app │
-│ | ├─ -godot-Label3D.text: '{name}{age}'| > inits 'Label3D' component (*) in Godot │
-│ +--------+ | │
-│ | │
-├─ -GODOT-version: '4.3' | > exporters/authors can report targeted version │
-├─ -AFRAME-version: '1.6.0' | and (optionally) hint component-repo│
-├─ -AFRAME-info: 'https://git.benetou.fr/comps' │
-│ | │
-+────────────────────────────────────────────────────────────────────────────────────────────────────────+
-<vendorname>-<component|version>.<key> [string/boolean/float/int]-valueString-templatevalues are evaluated as per URI Templates (RFC6570) Level 1.
- --- -This ‘separating of mechanism from policy’ (unix rule) does somewhat break portability of an XR experience, but still prevents (E-waste of) handcoded virtual worlds. It allows for (XR experience) metadata to survive in future 3D engines and scene-fileformats.
-
- -
The only dynamic parts are W3C Media Fragments and URI Templates (RFC6570).
-The use of URI Templates is limited to pre-defined variables and Level0 fragments-expansion only, which makes it quite safe.
-n fact, it is much safer than relying on a scripting language (javascript) which can change URN too.
- -
Q: Why is everything HTTP GET-based, what about POST/PUT/DELETE HATEOS
-A: Because it’s out of scope: XR Fragment specifies a read-only way to surf XR documents. These things belong in the application layer (for example, an XR Hypermedia browser can decide to support POST/PUT/DELETE requests for embedded HTML thru src values)
Q: Why isn’t there support for scripting, URI Template Fragments are so limited compared to WASM & javascript
-A: This is out of scope as it unhyperifies hypermedia, and this is up to XR hypermedia browser-extensions.
Historically scripting/Javascript seems to been able to turn webpages from hypermedia documents into its opposite (hyperscripted nonhypermedia documents).
In order to prevent this backward-movement (hypermedia tends to liberate people from finnicky scripting) XR Fragment uses W3C Media Fragments and URI Templates (RFC6570), to prevent unhyperifying itself by hardcoupling to a particular markup or scripting language.
-XR Fragments supports filtering objects in a scene only, because in the history of the javascript-powered web, showing/hiding document-entities seems to be one of the most popular basic usecases.
-Doing advanced scripting & networkrequests under the hood are obviously interesting endavours, but this is something which should not be hardcoupled with XR Fragments or hypermedia.
This perhaps belongs more to browser extensions.
-Non-HTML Hypermedia browsers should make browser extensions the right place, to ‘extend’ experiences, in contrast to code/javascript inside hypermedia documents (this turned out as a hypermedia antipattern).
- -
- -
This document has no IANA actions.
- -- -
- -
| definition | -explanation | -
|---|---|
| human | -a sentient being who thinks fuzzy, absorbs, and shares thought (by plain text, not markuplanguage) | -
| scene | -a (local/remote) 3D scene or 3D file (index.gltf e.g.) | -
| 3D object | -an object inside a scene characterized by vertex-, face- and customproperty data. | -
| URI | -some resource at something somewhere via someprotocol (http://me.com/foo.glb#foo or e76f8efec8efce98e6f see interpeer.io) |
-
| URL | -something somewhere via someprotocol (http://me.com/foo.glb) |
-
| URN | -something at some domain (me.com/foo.glb) |
-
| metadata | -custom properties of text, 3D Scene or Object(nodes), relevant to machines and a human minority (academics/developers) | -
| XR fragment | -URI Fragment with spatial hints (which match the name of a 3D object-, camera-, animation-object) | -
| the XRWG | -wordgraph (collapses 3D scene to tags) | -
| the hashbus | -hashtags map to camera/scene-projections | -
| spacetime hashtags | -positions camera, triggers scene-preset/time | -
| teleportation | -repositioning the enduser to a different position (or 3D scene/file) | -
| sourceportation | -teleporting the enduser to the original XR Document of an src embedded object. |
-
| placeholder object | -a 3D object which with src-metadata (which will be replaced by the src-data.) | -
| src | -(HTML-piggybacked) metadata of a 3D object which instances content | -
| href | -(HTML-piggybacked) metadata of a 3D object which links to content | -
| filter | -URI Fragment(s) which show/hide object(s) in a scene based on name/tag/property (#cube&-price=>3) |
-
| visual-meta | -visual-meta data appended to text/books/papers which is indirectly visible/editable in XR. | -
| requestless metadata | -metadata which never spawns new requests (unlike RDF/HTML, which can cause framerate-dropping, hence not used a lot in games) | -
| FPS | -frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible | -
| introspective | -inward sensemaking (“I feel this belongs to that”) | -
| extrospective | -outward sensemaking (“I’m fairly sure John is a person who lives in oklahoma”) | -
◻ |
-ascii representation of an 3D object/mesh | -
| (un)obtrusive | -obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words | -
| flat 3D object | -a 3D object of which all verticies share a plane | -
| BibTeX | -simple tagging/citing/referencing standard for plaintext | -
| BibTag | -a BibTeX tag | -
| (hashtag)bibs | -an easy to speak/type/scan tagging SDL (see here which expands to BibTex/JSON/XML | -
NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible -
XR Fragments is in a sense, a <b>heuristical 3D format</b> or meta-format, which leverages heuristic rules derived from any 3D scene or well-established 3D file formats, to extract meaningful features from scene hierarchies. -
- -These heuristics, enable features that are both meaningful and consistent across different scene representations, allowing <b>higher interop</b> between fileformats, 3D editors, viewers and game-engines.
Being able to use the same URI Fragment DSL for navigation (href: #foo) as well as interactions (href: xrf://#foo) greatly simplifies implementation, increases HFL, and reduces need for scripting languages. -
| principle | -3D URL | -HTML 2D URL | -
|---|---|---|
| the XRWG | -wordgraph (collapses 3D scene to tags) | -Ctrl-F (find) | -
| the hashbus | -hashtags alter camera/scene/object-projections | -hashtags alter document positions | -
| src metadata | -renders content and offers sourceportation | -renders content | -
| href metadata | -teleports to other XR document | -jumps to other HTML document | -
| href metadata | -triggers predefined view | -Media fragments | -
| href metadata | -triggers camera/scene/object/projections | -n/a | -
| href metadata | -draws visible connection(s) for XRWG 'tag' | -n/a | -
| href metadata | -filters certain (in)visible objects | -n/a | -
| href metadata | -href="xrf://#-foo&bar" | -href="javascript:hideFooAndShowBar()` | -
| - | (this does not update topLevel URI) | -(this is non-standard, non-hypermediatic) | -
An important aspect of HFL is that URI Fragments can be triggered without updating the top-level URI (default href-behaviour) thru their own 'bus' (xrf://#.....). This decoupling between navigation and interaction prevents non-standard things like (href:javascript:dosomething()). -
Example: ://foo.com/my3d.gltf#room1&prio=-5&t=0,100 -
| Demo | -Explanation | -
|---|---|
| room1 | -vector/coordinate argument e.g. | -
| room1&cam1 | -combinators | -
this is already implemented in all browsers -
Every 3D fileformat supports named 3D object, and this name allows URLs (fragments) to reference them (and their children objects). -
It also allows sourceportation, which basically means the enduser can teleport to the original XR Document of an src embedded object, and see a visible connection to the particular embedded object. Basically an embedded link becoming an outbound link by activating it. -
* = last wins in case of non-unique names -
A fallback-mechanism to turn 3D files into -XR Movies without editing them.
-NOTE: in the examples below we use the href-heuristic, but also the .xrf. chained-extension applies here. -
NOTE: Linux's setfattr/getfattr is xattr on mac, and Set-Content/Get-content on Windows. See -pxattr for lowlevel access.
This will make object button clickable, and teleport the user to object roomB. -
-In THREE.js-code this would boil down to: -
XR Fragments allows deeplinking of 3D objects by mapping objectnames to URI fragments -
XR Fragments does not look at XR (or the web) thru the lens of HTML or URLs. -
-But approaches things from a higherlevel local-first 3D hypermedia browser-perspective.
-?-linked and #-linked navigation are JUST one possible way to implement XR Fragments: the essential goal is to allow a Hypermediatic FeedbackLoop (HFL) between external and internal 4D navigation. -
| fragment | -type | -example | -info | -
|---|---|---|---|
| #...... | -vector3 | -#room1 #room2 #cam2 | -positions/parents camera(rig) (or XR floor) to xyz-coord/object/camera and upvector | -
| #t=0,2&loop | -play (and loop) 3D animation from 0 seconds till 2 seconds | -
| key | -type | -example (JSON) | -function | -existing compatibility | -
|---|---|---|---|---|
| href | -string | -"href": "b.gltf" | -XR teleport | -custom property in 3D fileformats | -
NOTE: hashbus links (xrf://#foo&bar) don't change the toplevel URL, which makes it ideal for interactions (in contrast to typical #roomC navigation, which benefit back/forward browser-buttons), see <a href="#hashbus">hashbus</a> for more info. -
these allow for XR Movies with a controllable timeline using href URI's with Media Fragments -
-Examples: #+menu to show a object, #-menu to hide a menu, #!menu to teleport a menu, #*block to clone a grabbable block, #|object to share an object -
-This will teleport the user to whiteroom and moves object explainer and exitmenu in front of the user. -
NOTE: level2 teleportation links, as well as instancing mitigates the 'broken embedded image'-issue of HTML: always attaching the href-values to a 3D (preview) object (that way broken links will not break the design). -
NOTE: combining instance-operators allows dynamic construction of 3D scenes (#london&!welcomeMenu&!fadeBox e.g.) -
NOTE: this is basically the -#! operator which infinitely clones the referenced object (instead of repositioning the object).
How to show/hide/group material- or object- or animations by name? -
NOTE: to hide a skybox when importing/loading a 3D file (force AR) is possible by linking to `https://my.org/foo.glb#-skybox or https://my.org/foo.glb#-skyboxmaterial -
-This URL can be fed straight into -Web Share API orxdg-open
NOTE: sharing is limited to (internal objects) via xrf: scheme-only -
Usecase: for non-shareable URLs like href: xrf:#t=4,5, to display a stateful msg e.g.). -
compliance with RFC 3986: unimplemented/unknown URI schemes (xrf:... e.g.) will not update the top-level URL -
Example URL: ://foo/world.gltf#room1&t=10&cam -
| fragment | -type | -example value | -
|---|---|---|
| href | -string (uri or predefined view) | -#room1 -#room1 -://somefile.gltf#room1 - |
-
By default position 0,0,0 of the 3D scene represents the walkable plane, however this is overridden when the following applies: -
optionally the viewer can offer thumbstick, mouse or joystick teleport-tools for non-roomscale VR/AR setups. -
NOTE: please always start aria-description with a verb to aid transcripts. -
Example: object 'tryceratops' with aria-description: is a huge dinosaurus standing on a #mountain generates transcript #tryceratops is a huge dinosaurus standing on a #mountain, where the hashtags are clickable XR Fragments (activating the visible-links in the XR browser). -
| metadata key | -example value | -
|---|---|
| aria-description, og:description, dc:description | -An immersive experience about Triceratops (*) | -
| SPDX | -CC0-1.0 | -
| dc:creator | -John Doe | -
| dc:title, og:title | -'Triceratops` (*) | -
| og:site_name | -https://xrfragment.org | -
| dc.publisher | -NLNET | -
| dc.date | -2024-01-01 | -
| dc.identifier | -XRFRAGMENT-001 | -
| journal (bibTeX) | -{Future Of Text Vol 3}, | -
* = these are interchangable (only one needs to be defined) -
These attributes can be scanned and presented during an href or src eye/mouse-over. -
Priority Order and Precedence, otherwise fallback applies -
Example 1 In case of the OMI_LINK glTF extension (href: https://nlnet.nl) and an XR Fragment (href: #otherroom or href: otherplanet.glb), it is clear that https://nlnet.nl should open in a browsertab, whereas the XR Fragment links should teleport the user. If the OMI_LINK contains an XR Fragment (#room1 e.g.) a teleport should be performed only (and other [overlapping] metadata should be ignored). -Example 2 If an Extensions uses XR Fragments in URI's (href: #otherroom or href: xrf://-walls in OMI_LINK e.g.), then perform them according to XR Fragment spec (teleport user). But only once: ignore further overlapping metadata for that usecase. -
| what | -XR metadata | -Lowest common denominator | -
|---|---|---|
| CSS | -vendor-agnostic | -2D canvas + object referencing/styling | -
| XR Fragments | -vendor-agnostic | -3D camera + object(file) load/embed/click/referencing | -
| Vendor prefixs | -vendor-specific | -Specialized Entity-Component implementation | -
Why? Because not all XR interactions can/should be solved/standardized by embedding XR Fragments into any 3D file. -The lowest common denominator between 3D engines is the 'entity'-part of their entity-component-system (ECS). The 'component'-part can be progressively enhanced via vendor prefixes. -
This 'separating of mechanism from policy' (unix rule) does somewhat break portability of an XR experience, but still prevents (E-waste of) handcoded virtual worlds. It allows for (XR experience) metadata to survive in future 3D engines and scene-fileformats. -
| definition | -explanation | -
|---|---|
| human | -a sentient being who thinks fuzzy, absorbs, and shares thought (by plain text, not markuplanguage) | -
| scene | -a (local/remote) 3D scene or 3D file (index.gltf e.g.) | -
| 3D object | -an object inside a scene characterized by vertex-, face- and customproperty data. | -
| URI | -some resource at something somewhere via someprotocol (http://me.com/foo.glb#foo or e76f8efec8efce98e6f |
-
| URL | -something somewhere via someprotocol (http://me.com/foo.glb) | -
| URN | -something at some domain (me.com/foo.glb) | -
| metadata | -custom properties of text, 3D Scene or Object(nodes), relevant to machines and a human minority (academics/developers) | -
| XR fragment | -URI Fragment with spatial hints (which match the name of a 3D object-, camera-, animation-object) | -
| the XRWG | -wordgraph (collapses 3D scene to tags) | -
| the hashbus | -hashtags map to camera/scene-projections | -
| spacetime hashtags | -positions camera, triggers scene-preset/time | -
| teleportation | -repositioning the enduser to a different position (or 3D scene/file) | -
| sourceportation | -teleporting the enduser to the original XR Document of an src embedded object. | -
| placeholder object | -a 3D object which with src-metadata (which will be replaced by the src-data.) | -
| src | -(HTML-piggybacked) metadata of a 3D object which instances content | -
| href | -(HTML-piggybacked) metadata of a 3D object which links to content | -
| filter | -URI Fragment(s) which show/hide object(s) in a scene based on name/tag/property (#cube&-price=>3) | -
| visual-meta | -|
| requestless metadata | -metadata which never spawns new requests (unlike RDF/HTML, which can cause framerate-dropping, hence not used a lot in games) | -
| FPS | -frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible | -
| introspective | -inward sensemaking ("I feel this belongs to that") | -
| extrospective | -outward sensemaking ("I'm fairly sure John is a person who lives in oklahoma") | -
| ◻ | -ascii representation of an 3D object/mesh | -
| (un)obtrusive | -obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words | -
| flat 3D object | -a 3D object of which all verticies share a plane | -
| BibTeX | -simple tagging/citing/referencing standard for plaintext | -
| BibTag | -a BibTeX tag | -
| (hashtag)bibs | -an easy to speak/type/scan tagging SDL ( |
-
-stream: IETF -area: Internet -status: informational -author: Leon van Kammen -date: 2023-04-12T00:00:00Z -workgroup: Internet Engineering Task Force -value: draft-XRMACROS-leonvankammen-00 -- - - -
This draft offers a specification for embedding macros in existing 3D scenes/assets, to offer simple interactions and configure the renderer further.
-Together with URI Fragments, it allows for rich immersive experiences without the need of a complicated sandboxed scripting languages.
--Almost every idea in this document is demonstrated at https://xrfragment.org, as this spec was created during the XR Fragments spec.
-
How can we add more features to existing text & 3D scenes, without introducing new dataformats?
-Historically, there’s many attempts to create the ultimate markuplanguage or 3D fileformat.
-Their lowest common denominator is: (co)authoring using plain text.
-Therefore, XR Macros allows us to enrich/connect existing dataformats, by offering a polyglot notation based on existing notations:
-- -NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible
-
!clickme: fog=0,10 e.g.)| symbol to 🎲 roundrobin variable values (!toggleme: fog=0,10|fog=0,1000 e.g.)!setlocal: foo=1 writes foo:1 metadata to the object containing the !setlocal metadata)!setfoo: #foo=1 writes foo:1 metadata to the root scene-node)-- -These very simple principles allow for rich interactions and dynamic querying
-
See appendix below in case certain terms are not clear.
- -(XR) Macros can be embedded in 3D assets/scenes.
-Macros enrich existing spatial content with a lowcode, limited logic-layer, by recursive (economic) use of the querystring syntax (which search engines and XR Fragments already uses.
-This is done by allowing string/integer variables, and the | symbol to roundrobin variable values.
-Macros also act as events, so more serious scripting languages can react to them as well.
| key | -type | -example (JSON) | -function | -existing compatibility | -
|---|---|---|---|---|
@bg |
-string | -"@bg":"#cube" |
-bg: binds fog near/far based to cube x/y/z (anim) values | -custom property in 3D fileformats | -
@fog |
-string | -"@fog":"#cube" |
-fog: binds fog near/far based to cube x/y (anim) values | -custom property in 3D fileformats | -
@scroll |
-string | -"@scroll":"#cube" |
-texturescrolling: binds texture x/y/rot based to cube x/y/z (anim) values | -custom property in 3D fileformats | -
@emissive |
-string | -"@emissive":"#cube" |
-day/night/mood: binds material’s emissive value to cube x/y/z (anim) values | -custom property in 3D fileformats | -
| custom property | -value | -trigger when | -
|---|---|---|
| !clickme | -bg=1,1,1&foo=2 | -object clicked | -
| custom property | -value | -trigger when | -
|---|---|---|
| # | -foo=1 | -scene | -
| !clickme | -q=foo>2&bg=1,1,1 | -object clicked and foo > 2 | -
-- -when a user clicks an object with the custom properties above, it should set the backgroundcolor to
-1,1,1whenfoois greater than2(see previous example)
| custom property | -value | -trigger when | -
|---|---|---|
| !cycleme | -day|noon|night | -object clicked | -
| day | -bg=1,1,1 | -roundrobin | -
| noon | -bg=0.5,0.5,0.5 | -roundrobin | -
| night | -bg=0,0,0&foo=2 | -roundrobin | -
-- -when a user clicks an object with the custom properties above, it should trigger either
-daynoonornightin roundrobin fashion.
| custom property | -value | -trigger when | -
|---|---|---|
| # | -random | -scene loaded | -
| #random | -random | -URL contains #random | -
| !random | -day|noon|night | -#random, # or click | -
| day | -bg=1,1,1 | -roundrobin | -
| noon | -bg=0.5,0.5,0.5 | -roundrobin | -
| night | -bg=0,0,0&foo=2 | -roundrobin | -
| custom property | -value | -trigger when | -
|---|---|---|
| !random | -!day | -!noon | -
| !day | -bg=1,1,1 | -clicked in contextmenu | -
| !noon | -bg=0.5,0.5,0.5 | -clicked in contextmenu | -
| !night | -bg=0,0,0&foo=2 | -clicked in contextmenu | -
-- -When interacting with an object with more than one
-!-macro, the XR Browser should offer a contextmenu to execute a macro.
In a similar way, when any !-macro is present on the sceneroot, the XR Browser should offer a context-menu to execute those macro’s.
click object with (!clickme:AR or !clickme: !reset e.g.)
◻
- │
- └── does current object contain this property-key (`AR` or `!reset` e.g.)?
- └── no: is there any (root)object containing property `AR`
- └── yes: evaluate its (roundrobin) XR macro-value(s) (and exit)
- └── no: trigger URL: #AR
-click object with (!clickme:#AR|#VR e.g.)
◻
- │
- └── apply the roundrobin (rotate the options, value `#AR` becomes `#VR` upon next click)
- └── is there any object with property-key (`#AR` e.g.)?
- └── no: just update the URL to `#AR`
- └── yes: apply its value to the scene, and update the URL to `#AR`
-
-click object with (`!clickme`:`!foo|!bar|!flop` e.g.)
-◻
- │
- └── apply the roundrobin (rotate the options, value !foo becomes !bar upon next click)
- └── is there any object with property-key (!foo e.g.)?
- └── no: do nothing
- └── yes: apply its value to the scene
-“`
-- -Note that only macro’s can trigger roundrobin values or contextmenu’s, as well as roundrobin values never ending up in the toplevel URL.
-
This document has no IANA actions.
- -| definition | -explanation | -
|---|---|
| scene | -a (local/remote) 3D scene or 3D file (index.gltf e.g.) | -
| 3D object | -an object inside a scene characterized by vertex-, face- and customproperty data. | -
| XR fragments | -URI Fragment with spatial hints like #pos=0,0,0&t=1,100 e.g. |
-
| query | -an URI Fragment-operator which queries object(s) from a scene like #q=cube |
-
| FPS | -frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible | -
◻ |
-ascii representation of an 3D object/mesh | -
| (un)obtrusive | -obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words | -
NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible -
These very simple principles allow for rich interactions and dynamic querying -
| key | -type | -example (JSON) | -function | -existing compatibility | -
|---|---|---|---|---|
| @bg | -string | -"@bg":"#cube" | -bg: binds fog near/far based to cube x/y/z (anim) values | -custom property in 3D fileformats | -
| @fog | -string | -"@fog":"#cube" | -fog: binds fog near/far based to cube x/y (anim) values | -custom property in 3D fileformats | -
| @scroll | -string | -"@scroll":"#cube" | -texturescrolling: binds texture x/y/rot based to cube x/y/z (anim) values | -custom property in 3D fileformats | -
| @emissive | -string | -"@emissive":"#cube" | -day/night/mood: binds material's emissive value to cube x/y/z (anim) values | -custom property in 3D fileformats | -
| custom property | -value | -trigger when | -
|---|---|---|
| !clickme | -bg=1,1,1&foo=2 | -object clicked | -
| custom property | -value | -trigger when | -
|---|---|---|
| # | -foo=1 | -scene | -
| !clickme | -q=foo>2&bg=1,1,1 | -object clicked and foo > 2 | -
when a user clicks an object with the custom properties above, it should set the backgroundcolor to 1,1,1 when foo is greater than 2 (see previous example) -
| custom property | -value | -trigger when | -
|---|---|---|
| !cycleme | -day|noon|night | -object clicked | -
| day | -bg=1,1,1 | -roundrobin | -
| noon | -bg=0.5,0.5,0.5 | -roundrobin | -
| night | -bg=0,0,0&foo=2 | -roundrobin | -
when a user clicks an object with the custom properties above, it should trigger either day noon or night in roundrobin fashion. -
| custom property | -value | -trigger when | -
|---|---|---|
| # | -random | -scene loaded | -
| #random | -random | -URL contains #random | -
| !random | -day|noon|night | -#random, # or click | -
| day | -bg=1,1,1 | -roundrobin | -
| noon | -bg=0.5,0.5,0.5 | -roundrobin | -
| night | -bg=0,0,0&foo=2 | -roundrobin | -
| custom property | -value | -trigger when | -
|---|---|---|
| !random | -!day | -!noon | -
| !day | -bg=1,1,1 | -clicked in contextmenu | -
| !noon | -bg=0.5,0.5,0.5 | -clicked in contextmenu | -
| !night | -bg=0,0,0&foo=2 | -clicked in contextmenu | -
When interacting with an object with more than one !-macro, the XR Browser should offer a contextmenu to execute a macro. -
Note that only macro's can trigger roundrobin values or contextmenu's, as well as roundrobin values never ending up in the toplevel URL. -
| definition | -explanation | -
|---|---|
| scene | -a (local/remote) 3D scene or 3D file (index.gltf e.g.) | -
| 3D object | -an object inside a scene characterized by vertex-, face- and customproperty data. | -
| XR fragments | -URI Fragment with spatial hints like #pos=0,0,0&t=1,100 e.g. | -
| query | -an URI Fragment-operator which queries object(s) from a scene like #q=cube | -
| FPS | -frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible | -
| ◻ | -ascii representation of an 3D object/mesh | -
| (un)obtrusive | -obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words | -