[x3d-public] allowing full capabilities for X3D node reuse with Inline EXPORT/IMPORT AS/USE
Don Brutzman
don.brutzman at gmail.com
Thu Oct 9 14:14:57 PDT 2025
Wow this is great Holger, thanks for sharing that excellent example. I
think this will really provide a big step up for our HAnim development work.
When you are ready, I am keen to test it out with Windows installer for
sunrize, that has really accelerated and improved my ability to write &
debug javascript inside a ProtoDeclare.
Meanwhile, the prototype implementation for HAnimPosePrototype.x3d that
I've been working on is coming along, but I am running into problems
"walking the tree" of an HAnimHumanoid because I am not able to access
fields properly. Many times when I try to dereference a node to get its
name, am getting 'undefined' as a result. Much online search and a few
variations didn't help, so there are likely some basic mistakes occurring.
This is probably due to an incorrect understanding on my part. Please
don't feel like I am asking you to debug it, but you (or someone else on
the list) might see poor JavaScript invocations that are preventing the
source from working. Link follow to latest version and trace statements on
console log. As might be expected, results are consistent between my local
Sunrize and online Playground and online X_ITE.
- X3D Example Archives: Humanoid Animation, Pose, HAnim Pose Prototype
- Define an experimental new node to simply capture a single pose for an
HAnimHumanoid model. Expected usage is to allow HAnimHumanoid to contain
multiple Pose nodes which can be activated and composed.
- (scroll down bottom pane to see ecmascript: source contained in Script
inside the model)
-
https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Pose/HAnimPosePrototypeIndex.html
-
https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Pose/HAnimPosePrototype.x3d
(This version is loading an Inline copy of JinLOA2 Humanoid so everything
is right there, and there are no possible EXPORT/IMPORT complications for
that Humanoid.)
---------------------
found Pose FaceLeft, enabled=true, traceEnabled=true
[HAnimPoseScript : initializing Pose FaceLeft]
[HAnimPoseScript : loa=0 description=Only modify humanoid_root Joint node
to face left]
[HAnimPoseScript : numberPoseJoints= 2]
// the following is an expected diagnostic that is working correctly
[HAnimPoseScript : *** [error] node type mismatch,
poseJoints[1]=HAnimSegment { } name=specialTestCase (should be HAnimJoint,
ignored)]
[HAnimPoseScript : outputVrmlString=
DEF OI_humanoid_root OrientationInterpolator { key [0, 1] keyValue [0 1 0
0, 0 1 0 0] }
# ROUTE HAnimPoseClock.fraction_changed TO OI_humanoid_root.set_fraction
]
[HAnimPoseScript : jointOrientationInterpolators.length=1 # size is correct]
[HAnimPoseScript : jointOrientationInterpolators.toString()=
OrientationInterpolator { } ### TODO missing fields]
[HAnimPoseScript : jointOrientationInterpolators JSON.stringify=
{"0":{"metadata":null,"key":{"0":0,"1":1},"keyValue":{"0":{},"1":{}},"value_changed":{}}}
### TODO partial fields]
[HAnimPoseScript : countPoseJoints() complete]
[HAnimPoseScript : starting countHumanoidSkeletonJoints()]
[HAnimPoseScript : parentHAnimHumanoid.name=JinLOA2=JinLOA2]
skeletonNode=HAnimJoint { }, name=undefined (console.log)
[HAnimPoseScript : skeletonNode=HAnimJoint { }, name=undefined]
[HAnimPoseScript : *** TODO why is skeletonNode.name not
retrievable/referencable?]
[HAnimPoseScript : parentHAnimHumanoid.skeleton=HAnimJoint { }
name=undefined]
[HAnimPoseScript : parentHAnimHumanoid.skeleton.length=1]
[HAnimPoseScript : invoking countChildJointsRecurse() to walk the tree...]
[HAnimPoseScript : *** recursion trace: nextNode=HAnimJoint { },
nextNode.name=undefined, nextNodeObject=HAnimJoint { },
nextNodeObject.name=undefined]
[HAnimPoseScript : *** TODO error, parameter nextNode appears to lose
fields and perhaps context when passed into next method]
[HAnimPoseScript : recursion found HAnimJoint { } name=undefined with
counter=1]
[HAnimPoseScript : HAnimJoint name=undefined has no children,
backtracking...]
[HAnimPoseScript : found numberSkeletonJoints=1 total]
[HAnimPoseScript : Pose FaceLeft initialization() complete]
---------------------
found Pose A, enabled=true, traceEnabled=true
[HAnimPoseScript : initializing Pose A]
[HAnimPoseScript : loa=1 description=experimental pose]
[HAnimPoseScript : numberPoseJoints= 2]
[HAnimPoseScript : outputVrmlString=
DEF OI_l_shoulder OrientationInterpolator { key [0, 1] keyValue [0 1 0 0, 0
1 0 0] }
# ROUTE HAnimPoseClock.fraction_changed TO OI_l_shoulder.set_fraction
DEF OI_r_shoulder OrientationInterpolator { key [0, 1] keyValue [0 1 0 0, 0
1 0 0] }
# ROUTE HAnimPoseClock.fraction_changed TO OI_r_shoulder.set_fraction
]
[HAnimPoseScript : jointOrientationInterpolators.length=2 # size is correct]
[HAnimPoseScript : jointOrientationInterpolators.toString()=
[
OrientationInterpolator { }
OrientationInterpolator { }
] ### TODO missing fields]
[HAnimPoseScript : jointOrientationInterpolators JSON.stringify=
{"0":{"metadata":null,"key":{"0":0,"1":1},"keyValue":{"0":{},"1":{}},"value_changed":{}},"1":{"metadata":null,"key":{"0":0,"1":1},"keyValue":{"0":{},"1":{}},"value_changed":{}}}
### TODO partial fields]
[HAnimPoseScript : countPoseJoints() complete]
[HAnimPoseScript : starting countHumanoidSkeletonJoints()]
[HAnimPoseScript : parentHAnimHumanoid.name=JinLOA2=JinLOA2]
skeletonNode=HAnimJoint { }, name=undefined (console.log)
[HAnimPoseScript : skeletonNode=HAnimJoint { }, name=undefined]
[HAnimPoseScript : *** TODO why is skeletonNode.name not
retrievable/referencable?]
[HAnimPoseScript : parentHAnimHumanoid.skeleton=HAnimJoint { }
name=undefined]
[HAnimPoseScript : parentHAnimHumanoid.skeleton.length=1]
[HAnimPoseScript : invoking countChildJointsRecurse() to walk the tree...]
[HAnimPoseScript : *** recursion trace: nextNode=HAnimJoint { },
nextNode.name=undefined, nextNodeObject=HAnimJoint { },
nextNodeObject.name=undefined]
[HAnimPoseScript : *** TODO error, parameter nextNode appears to lose
fields and perhaps context when passed into next method]
[HAnimPoseScript : recursion found HAnimJoint { } name=undefined with
counter=1]
[HAnimPoseScript : HAnimJoint name=undefined has no children,
backtracking...]
[HAnimPoseScript : found numberSkeletonJoints=1 total]
[HAnimPoseScript : Pose A initialization() complete]
---------------------
found Pose T, enabled=false, traceEnabled=false
---------------------
found Pose H, enabled=false, traceEnabled=false
---------------------
found Pose I, enabled=false, traceEnabled=false
Perhaps there is an example somewhere that can help, but I didn't find it.
Goal for now is to fully traverse an HAnimHumanoid tree, noting all
HAnimJoint nodes and their names.
Am running out of things to try... other eyes may do better than mine. TIA
for all scrutiny.
all the best, Don
--
X3D Graphics, Maritime Robotics, Distributed Simulation
Relative Motion Consulting https://RelativeMotion.info
On Thu, Oct 9, 2025 at 1:01 PM Holger Seelig <holger.seelig at yahoo.de> wrote:
> I have made an experimental implementation of this new feature. You can
> already use and play with it in the special preview playground:
>
>
> https://create3000.github.io/preview/playground/?url=https://create3000.github.io/Library/Tests/Components/Core/use-exported-node.x3dv
>
> This scene loads an inline file which exports a single green cube. This
> cube is imported into the scene and used a second time.
>
> There is also a experimental feature ‚USE before DEF‘ enabled in this
> preview playground. This feature seems important for me to get this all
> work in all cases.
>
> Best regards,
> Holger
>
> —
> Holger Seelig
> Leipzig, Germany
>
> holger.seelig at yahoo.de
> https://create3000.github.io/x_ite/
> https://patreon.com/X_ITE
>
>
>
> Am 09.10.2025 um 18:51 schrieb Don Brutzman via x3d-public <
> x3d-public at web3d.org>:
>
> Hi Doug. Thanks for looking this over.
>
> I meant to also note earlier that this proposed change in semantics has no
> effect on any existing EXPORT/IMPORT statements in any existing X3D
> models, versions 3.0 through 4.0.
>
> Am glad to see you describing how FreeWrl supports EXPORT/IMPORT to date.
>
> Certainly refactoring half a gazillion lines of code is likely not
> worthwhile for such an extensibility feature... don't want to risk
> provoking side-effect problems. Unless you want to, of course... :)
>
> I'm following your points. Seems sensible, but maybe any changes to the
> existing functionality you describe is pretty similar to other handling
> that is already in place. Please consider the following short reactions,
> and correct me if wrong:
>
> - Inline nodes exist and receive few ROUTE connections, there are not
> many fields there (url load etc.)
> - IMPORT creates a node reference that points somewhere in the scene
> subgraph loaded by Inline
> - That IMPORT reference can already send/receive events via ROUTE, as
> long defined in the spec.
> - In essence, the proposal says such a node reference might be treated
> in the same manner as other USE nodes, which are also node references.
>
> Again appreciate all consideration. Even if this is impractical for
> FreeWrl, your opinion on feasibility in general remains welcome. Am not
> trying to check boxes on a feature list, and am not trying to push a
> nontrivial architectural change. Rather am trying to enable significantly
> more scalable extensibility by removing a small existing constraint on
> usage.
>
> p.s. curiously, since the specification intentionally never mandates error
> responses, it seems like a browser implementation might satisfactorily
> permit IMPORT node references to behave similarly as USE node references,
> if it wants. hmmm...
>
> Have fun with X3D! 😀
>
> all the best, Don
> --
> X3D Graphics, Maritime Robotics, Distributed Simulation
> Relative Motion Consulting https://RelativeMotion.info
> <https://relativemotion.info/>
>
>
> On Thu, Oct 9, 2025 at 9:14 AM GPU Group <gpugroup at gmail.com> wrote:
>
>> Don,
>> "synchronization" I suspect the change would break (25 year old,
>> currently unmaintained) freewrl. I like the use-case you mention for the
>> change, seems well worth a big change. Final nail in freewrl coffin? Not
>> necessarily but would require insight and ambition to refactor 500,000
>> lines of code to allow a layer of abstraction / uncertainty around every
>> node and route in the scenegraph.
>> -Doug
>> more..
>> tests for new conformance would be
>> - if routes can dangle before an Inline is loaded, and after an Inline is
>> unloaded
>> - by dangle I mean point harmlessly TO nothing / unloaded node, without
>> being garbage collected
>> - no error or warning is issued when a route dangles
>> - if Inlined nodes are to be treated like regular scenegraph nodes, would
>> that mean all routes to regular scenegraph nodes should be able to dangle?
>> - current specs: a test for deleting a regular scenegraph node: have an
>> active route to it, and see if something breaks when the node is deleted
>> -- would that need to change so instead of garbage collecting routes to
>> deleted nodes, they dangle, and (somehow) are allowed to hook back up to
>> new added nodes?
>> freewrl current Inline mechanism:
>> - Inlines are loaded, parsed in a separate thread, and can be loaded and
>> unloaded with true/false field on Inline
>> - on each rendering frame, when Inline node is rendered/drawn/visited, it
>> does a little work to check the load progress/status, and makes any changes
>> to IMPORT routes and AS nodes as needed
>> - freewrl uses special routes to Inlined IMPORTed nodes, which can
>> 'dangle' (called weak routes in freewrl) while waiting for the inline to
>> load (rest of scene can be rendering).
>> - the special routes get an extra complex lookup to see if the TO node is
>> loaded
>> - versus deleting a regular scenegraph node would trigger a search for
>> routes to the deleted node, and the routes would be deleted/garbage
>> collected too
>> - and normal routes, freewrl uses memory addresses for start and end node
>> fields, and does a memory copy of field value during routing loop, (versus
>> weak/dangling route complex lookup in separate loop)
>> - when an Inline EXPORTed node is loaded it is allocated to a memory
>> address via malloc. when unloaded and free(), and reloaded and
>> reallocated, it would be loaded in a different memory address, so can't do
>> a simple memcpy with old address during routing, needs to check if node
>> loaded and what's the new memory address
>> SUMMARY: freewrl seems to be missing a layer of abstraction around or
>> flag for each node and route that would allow a USE of an Inlined AS node
>> and IMPORT route to enjoy equal status in the scenegraph. Not immediately
>> obvious how to fix / refactor.
>>
>>
>>
>>
>>
>> On Wed, Oct 8, 2025 at 1:27 PM Don Brutzman via x3d-public <
>> x3d-public at web3d.org> wrote:
>>
>>> [BLUF summary: proposed specification change to allow regular re-USE of
>>> imported node references.]
>>>
>>> Am trying to write a prototype for HAnim, and hoped that I might EXPORT
>>> a large model so that a smaller scene might IMPORT the HAnimHumanoid for
>>> further reuse (as a USE node in a prototype). Example EXPORT:
>>>
>>> - 3D Example Archives: Humanoid Animation, Characters, Jin LOA 2
>>> - Articulated 3D game character designed with a general graphics
>>> tool, then converted into an X3D HAnim model and available for IMPORT as
>>> JinLOA2.
>>> -
>>> https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Characters/JinLOA2Index.html
>>> - <!-- This node has an EXPORT
>>> <https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Characters/JinLOA2.html#JinLOA2> connection
>>> that can exchange events with a parent X3D model. -->
>>> <HAnimHumanoid DEF='hanim_JinLOA2
>>> <https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Characters/JinLOA2.html#hanim_JinLOA2>
>>> ' loa='2' name='JinLOA2' scale='0.0225 0.0225 0.0225'> on line 30
>>> <https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Characters/JinLOA2.html#30>
>>>
>>> - <EXPORT localDEF='hanim_JinLOA2
>>> <https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Characters/JinLOA2.html#hanim_JinLOA2>
>>> ' AS='JinLOA2'/> on line 1319
>>> <https://www.web3d.org/x3d/content/examples/HumanoidAnimation/Characters/JinLOA2.html#1319>
>>>
>>>
>>> Hmmm, please notice that medium-size HAnim model is (1319 - 30 = 1289) lines
>>> long... gee, wouldn't it be nice to Inline and IMPORT that model in ~3
>>> lines instead, with added benefit of being able to reuse pose and motion
>>> animations with it also.
>>>
>>> However the current X3D Architecture appears to restrict the usage of
>>> imported nodes solely to receiving/sending events. That restriction
>>> permits writing ROUTE connections, but a blocker if trying to write a
>>> prototype or trying other node re-USE.
>>>
>>> EXPORT and IMPORT statements are rarely used, but have been around a
>>> long time... since X3D 3.0, about 25 years maybe. They have potential for
>>> great expressive power and extensibility (the X in X3D). However, am
>>> guessing that the reuse limitation of IMPORT nodes has likely inhibited our
>>> adoption. If I recall correctly, the primary objection (way back then) to
>>> allowing full access to an imported node reference was uncertainty about
>>> how it might all work, perhaps complicated by run-time synchronization
>>> concerns.
>>>
>>> We have come a long way since then. It seems pretty clear that an
>>> Inline node loads an external scene graph into the current scene graph.
>>> Further, the EXPORT statement identifies a specific node (sub graph) within
>>> that inlined scene graph.
>>>
>>> The straightforward way to think about this: Inline EXPORT/IMPORT
>>> provides a reference to a node in the currently loaded scene graph. Given
>>> that the author has a reference to an active node, they ought to be able to
>>> utilize that node reference just like any other DEF/USE node reference.
>>>
>>> I propose we relax the legacy (25-year) restriction and allow IMPORT
>>> node references to be treated the same as USE node references.
>>>
>>> Towards that end, have written out suggested changes in the draft v4.1
>>> architecture, adding to a number of editorial improvements already
>>> accomplished as part of
>>>
>>> - Mantis 1470: add EXPORT/IMPORT field DESCRIPTION for X3D
>>> Architecture 4.1; also allow reuse
>>> - https://mantis.web3d.org/view.php?id=14701470: add EXPORT/IMPORT
>>> field DESCRIPTION for X3D Architecture 4.1
>>>
>>> Request review, considerations and reactions. The markup changes at
>>> first look complex but are essentially all geared towards the single
>>> objective of allowing re-use of IMPORT nodes. Lots of markup shows that
>>> there are few actual changes to existing prose, most of it is simply
>>> editorial re-organization for clarity.
>>>
>>> This is a good topic for this week's specification editors call on
>>> Friday (9 pacific).
>>> ______________________________
>>>
>>> For easy review, current markup follows. *First is Concepts.*
>>>
>>> - X3D Architecture v4.1, clause 4 Concepts, 4.4.6 EXPORT/IMPORT
>>> semantics
>>> -
>>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/concepts.html#ExportImportSemantics
>>>
>>> 4.4.6 EXPORT/IMPORT semantics Import/Export semantics
>>>
>>> Editors note: there are few actual changes here, most are simply
>>> switching the order of EXPORT and IMPORT. Added functionality: imported
>>> node reuse.
>>>
>>> The EXPORT feature allows authors to identify specific parts of an X3D
>>> model which might be safely shared and reused by other X3D models. The
>>> IMPORT feature allows authors to incorporate content defined within Inline
>>> nodes or created programmatically into the namespace of the containing file
>>> for the purposes of event routing and reusing scene subgraphs on a
>>> per-node basis. In contrast with external prototyping (see 4.4.5
>>> External prototype semantics
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/concepts.html#Externalprototypesemantics>),
>>> which allows access to individual fields of nodes defined as prototypes in
>>> external files, IMPORT provides access to all the fields of an externally
>>> defined node with a single statement (see 9.2.6 IMPORT statement
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/networking.html#IMPORTStatement>
>>> ).
>>>
>>> Importing nodes from an Inlined file is accomplished with two
>>> statements: EXPORT and IMPORT. IMPORT and EXPORT. The IMPORT statement
>>> is used in the containing file to define which nodes of an Inline are to be
>>> incorporated into the containing file's namespace. The EXPORT statement
>>> is used in the file being Inlined, to control access over which nodes
>>> within a file are visible to other files (see 9.2.5 EXPORT statement
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/networking.html#EXPORTStatement>).
>>> EXPORT statements are not allowed in prototype declarations. The IMPORT
>>> statement is used in the containing file to define which nodes of an Inline
>>> are to be incorporated into the containing file's namespace.
>>>
>>> In contrast with external prototyping (see 4.4.5 External prototype
>>> semantics
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/concepts.html#Externalprototypesemantics>),
>>> which allows access to individual fields of nodes defined as prototypes in
>>> external files, IMPORT provides access to all the fields of an externally
>>> defined node with a single statement (see 9.2.6 IMPORT statement
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/networking.html#IMPORTStatement>
>>> ).
>>>
>>> ______________________________
>>>
>>> *Next is the EXPORT statement.*
>>>
>>> - X3D Architecture v4.1, clause 9 Networking component, 9.2.5 EXPORT
>>> statement
>>> -
>>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/networking.html#EXPORTStatement
>>>
>>> 9.2.5 EXPORT statement
>>>
>>> The EXPORT statement is used within an X3D file to specify nodes that
>>> may be imported into other scenes when Inlining that file. Only named nodes
>>> exported with an EXPORT statement are eligible to be imported into another
>>> scene. file. DEF names are used to identify exported nodes. See 4.4.6
>>> EXPORT/IMPORT semantics
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/concepts.html#ExportImportSemantics> for
>>> further details.
>>>
>>> EXPORT statements may appear anywhere in the file and have the following
>>> form:
>>>
>>> EXPORT <NodeDEFName> [ AS <ExportedNodeDEFName> ]
>>> [DESCRIPTION "a simple description of intended EXPORT purpose"]
>>>
>>> EXPORT <NodeName> [ AS <ExportedNodeName> ]
>>>
>>> The EXPORT statement has the following components:
>>>
>>> 1. The local DEF name of the node to be exported if the current
>>> scene is retrieved externally via Inline,
>>> 2. An optional alternative DEF name that is used AS a default as an alias
>>> for the exported node when importing it into other scenes, files,
>>> 3. An optional simple DESCRIPTION of intended purpose for the node
>>> provided via EXPORT.
>>>
>>> The EXPORT statement has the following semantics:
>>>
>>> 4. Once imported into a containing scene, events may be routed to or
>>> from the fields of an exported node in exactly the same manner as
>>> any node defined with DEF.
>>> 5. Exported nodes imported into a containing scene may be referenced
>>> via a USE statement in the importing scene. may not be instanced via
>>> the USE statement.
>>> 6. Exportation may not be propagated across multiple files; that is,
>>> a node imported into one scene using the IMPORT statement may not then be
>>> further exported into another scene using the EXPORT statement.
>>> 7. Nodes shall not be exported from within the body of a PROTO
>>> declaration.
>>> 8. Any scene with an EXPORT statement shall apply UNIT statement
>>> adjustments as needed to the fields of any exported nodes and child nodes.
>>> 9. The EXPORT statement can appear wherever a ROUTE statement is
>>> allowed, and shall be contained within the Inline node to which it refers.
>>>
>>> The following example illustrates the use of the EXPORT statement
>>> (Classic VRML encoding):
>>>
>>> EXAMPLE
>>>
>>> DEF T1 Transform {
>>> # additional nodes and fields...
>>> }# additional nodes and fields...
>>>
>>> EXPORT T1 AS rootTransform
>>>
>>> In the above example, node T1 is exported for use by other X3D scenes.
>>> The optional AS keyword defines the exported name of *T1* as
>>> *rootTransform* (*i.e.*, other scenes may import the node only using
>>> the name rootTransform). All defined alias AS names shall also meet
>>> appropriate uniqueness requirements in the local DEF namespace of the
>>> parent scene.
>>>
>>> ______________________________
>>> *Next is the IMPORT statement.*
>>>
>>> - X3D Architecture v4.1, clause 9 Networking component, 9.2.6 IMPORT
>>> statement
>>> -
>>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/networking.html#IMPORTStatement
>>>
>>> 9.2.6 IMPORT statement
>>>
>>> The IMPORT statement is used within an X3D file to specify nodes, which
>>> are defined within Inline files or programmatically created content, that
>>> are to be brought into the namespace of the containing file for the
>>> purposes of event routing. Once a node is imported, events may be sent to
>>> its fields via ROUTEs, or routed from any fields of the node which have
>>> output events. DEF names are used to identify nodes. See 4.4.6
>>> EXPORT/IMPORT semantics
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/concepts.html#ExportImportSemantics> for
>>> further details.
>>>
>>> IMPORT statements may appear anywhere in the file and have the following
>>> form:
>>>
>>> IMPORT <InlineNodeDEFName>*.*<ExportedNameFromInlinedFile> [ AS
>>> <NewLocalNodeDEFName> ]
>>> [DESCRIPTION "a simple description of intended IMPORT purpose"]
>>>
>>> IMPORT <InlineNodeName>*.*<ExportedNameFromInlinedFile> [ AS
>>> <NewLocalNodeName> ]
>>>
>>> The IMPORT statement has the following components:
>>>
>>> 1. The DEF name of the Inline node that contains the node to be
>>> imported,
>>> 2. The DEF name of the node to import,
>>> 3. An optional alternative DEF name that is used AS as an alias for
>>> the imported node within the run-time name scope, to help prevent avoid
>>> potential DEF name clashes within the parent scene containing the
>>> IMPORT statement,
>>> 4. An optional simple DESCRIPTION of intended purpose for the node
>>> provided via IMPORT.
>>>
>>> The IMPORT statement has the following semantics:
>>>
>>> 5. Once imported, events may be routed to or from the fields of an imported
>>> node in the Inline scene, in exactly the same manner as any node
>>> defined locally with DEF.
>>> 6. Editors note: the following is an important change, otherwise an
>>> imported node cannot be utilized other than by receiving ROUTEd events (as
>>> shown by the InlineImport.x3d
>>> <https://www.web3d.org/x3d/content/examples/Basic/X3dSpecifications/InlineImportIndex.html>
>>> example).
>>> Nodes imported into an X3D scene using the IMPORT statement may be
>>> referenced not be instanced via the USE statement.
>>> 7. Only nodes that are exported from within the Inline scene via an
>>> EXPORT statement may be imported using a corresponding IMPORT statement.
>>> 8. The IMPORT statement can appear wherever a ROUTE statement is
>>> allowed, and shall follow the Inline node to which it refers.
>>>
>>> Any node reference that is obtained via IMPORT from an exporting scene
>>> is also available as a USE node in the importing scene. This requirement is
>>> necessary for the node reference retrieved by IMPORT to have full
>>> capabilities in the importing scene. Nevertheless, important
>>> synchronization considerations arise when one or more Inline models are
>>> loaded as part of the current scene graph.
>>>
>>> 9. A single Inline node is allowed to have multiple IMPORT
>>> statements. The state of nodes within that currently loaded Inline model
>>> are consistently maintained as part of the current scene.
>>> 10. Multiple Inline nodes with separate IMPORT statements are
>>> completely independent, even if each independent Inline is retrieving a
>>> copy of the same original model.
>>>
>>> The following example illustrates the use of the IMPORT statement
>>> (Classic VRML encoding syntax):
>>>
>>> EXAMPLE
>>>
>>> DEF MyInline I1 Inline {
>>> url "someurl.x3d"
>>> }
>>> IMPORT MyInline.rootTransform AS ImportedTransform I1.rootTransform AS I1Root ...
>>> # ROUTE events into the imported node, which is now a part of an Inline scene subgraph
>>> DEF PI PositionInterpolator { } { ... }
>>> ROUTE PI.value_changed TO ImportedTransform.set_translation I1Root.set_translation
>>>
>>> # also USE the imported node (and associated scene subgraph) elsewhere in the parent scene
>>> Group {
>>> USE ImportedTransform
>>> }
>>>
>>> # also USE the imported node when defining an instance of a MyNewTransform prototype
>>> MyNewTransform {
>>> children USE ImportedTransform
>>> }
>>>
>>> In the above example,
>>>
>>> - rootTransform is externally defined as a Transform node in the
>>> file someurl.x3d and exported via an EXPORT statement. (see 4.4.6
>>> Import/Export semantics
>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/concepts.html#ExportImportSemantics>
>>> ).
>>> - The optional AS keyword in the IMPORT statement defines an alias
>>> for the MyInline.rootTransform rootTransform DEF. , so that
>>> - Within the containing scene, the node is referenced using the AS
>>> alias name ImportedTransform. DEF name I1Root.
>>>
>>> All defined alias AS names shall also meet appropriate uniqueness
>>> requirements in the local DEF namespace of the parent scene.
>>>
>>> ______________________________
>>> Additional thanks to Joe Williams, Holger Seelig, and Nicholas Polys for
>>> contributing to this analysis and potential improvement.
>>>
>>> All feedback welcome! This simple functional refinement has potential
>>> for much X3D scalability and extensibility.
>>>
>>> Thanks in advance for considering the possibilities.
>>>
>>> all the best, Don
>>> --
>>> X3D Graphics, Maritime Robotics, Distributed Simulation
>>> Relative Motion Consulting https://RelativeMotion.info
>>> <https://relativemotion.info/>
>>> _______________________________________________
>>> x3d-public mailing list
>>> x3d-public at web3d.org
>>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>>>
>> _______________________________________________
> x3d-public mailing list
> x3d-public at web3d.org
> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20251009/f31a663d/attachment-0001.html>
More information about the x3d-public
mailing list