[x3d-public] InlineGeometry node and PLY format support in Castle Game Engine
Don Brutzman
don.brutzman at gmail.com
Thu Apr 16 12:31:08 PDT 2026
Thanks for prior discussions on smooth/sharp rendering and evaluation of
*creaseAngle* suitability. Simplest resolution seems to be adding a
SFBool *smooth
*field as a hint.
Image follows showing that authors also need to control single-sided versus
double-sided rendering, which can be accomplished as usual using the *solid
*field. Sometimes you want it, sometimes you don't. This screenshot
illustrates how single-sided rendering lets a user look through the inside
of a teapot's body and spout.
- X3D4AM, X3D for Advanced Modeling Examples Archive, Additive
Manufacturing, Teapot Inline Geometry Ply
<https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/TeapotInlineGeometryPlyIndex.html>
- Loading a classic teapot model in PLY format
-
https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/TeapotInlineGeometryPlyIndex.html
[image: image.png]
I don't think we need to worry about *ccw *or *convex *fields... that is
best left to the X3D player implementing this node. The mesh "is what it
is" and an author is choosing not to do conversions when they use
InlineGeometry node.
Additional thanks for review by X3D Ecology working group this week, also
another review session with Dick Puk. Refined specification prose
follows. Once again, all comments welcome.
- X3D Architecture v4.1 draft, clause 9 Networking component, 9.4.3
InlineGeometry
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/networking.html#InlineGeometry>
-
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/networking.html#InlineGeometry
9.4.3 InlineGeometry
InlineGeometry : X3DGeometryNode, X3DUrlObject {
SFTime [in,out] autoRefresh 0.0 [0,infinity)
SFTime [in,out] autoRefreshTimeLimit 3600.0 [0,infinity)
SFString [in,out] description ""
SFBool [in,out] load TRUE
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFBool [in,out] solid FALSE
SFBool [in,out] smooth TRUE
MFString [in,out] url [] [URI]
}
InlineGeometry loads geometry from an external file. The result provides a
polygonal mesh, set of lines, point cloud, parametric surface, or other
geometry.
The *smooth* field provides a hint to the browser whether smooth rendering
is preferred for a retrieved polygonal mesh.
The *solid* field is described in 11.2.3 Common geometry fields
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/rendering.html#CommonGeometryFields>.
For InlineGeometry, the default value of *solid* is FALSE since most usages
of retrieved meshes need two-sided rendering. Authors have the option to
change this value for single-sided rendering.
The *url* field can support loading a variety of file formats defining
polygonal mesh geometry. When the *url* field contains no values ([]), no
default geometry is provided. Required support by X3D browsers includes
both ASCII and binary encodings for the STL format (see STL
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/bibliography.html#STL>)
as well as the PLY polygonal geometry format (see PLY
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/bibliography.html#PLY>),
respectively. Other file types can be optionally supported by a browser.
If the *url* field refers to an X3D file or a VRML97 file, the first
geometry node found in that file (excluding both prototype declarations and
prototype instances) is used to provide the InlineGeometry contents. X3D
browsers shall recognize *url* fields that end with "#*DEFname*" to mean
the geometry node with DEF label of *DEFname* in the given X3D or VRML97
file.
The run-time system can support any number of 3D model resource types as
long as those follow the available Model Primary Content Type for
Multipurpose Internet Mail Extensions (MIME) model definition (see RFC2077
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/references.html#RFC2077>),
provide a registered content type (e.g., model/stl, text/plain etc.) (see
IANA_MEDIA
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/references.html#IANA_MEDIA>
and IANA_STL
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/references.html#IANA_STL>),
and can be determined with some form of content negotiation (see RFC9110
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/references.html#RFC9110>).
Support is recommended for both text and binary encodings associated with a
given model format, when so defined.
EXAMPLES
Shape {
geometry InlineGeometry { url [ "MyFavoriteMesh.stl" ] }
appearance USE FancyPaintAppearance # previously defined
}
Shape {
geometry InlineGeometry { url [ "HelloWorld.x3d#TextMessage" ] }
appearance USE FancyPaintAppearance # previously defined
}
NOTE Experimental variations of PLY format used for Gaussian Splat
rendering are not expected for InlineGeometry. Such capabilities are better
supported by Inline node loading of glTF models.
Editors notes.
1. InlineGeometry results differ from an Inline node, which produces an
X3DChildNode scene subgraph implementing the X3DBoundedObject interface. An
Inline node cannot be used as the *geometry* field of a Shape.
2. Results from browser loading may be any kind of polygonal mesh or
parametric surface as an X3DGeometryNode instance (e.g. IndexedFaceSet,
TriangleSet, Extrusion, QuadSet etc.) but cannot be further manipulated or
animated by events from the scene.
3. Direct loading of such geometry files eliminates the need for prior
model conversion into X3D, and adds model flexibility when applying
Appearance to the result.
4. Have listed "required support" of STL/PLY formats rather than
"recommended support" since models described using these two formats are
primary use cases, and numerous open-source conversion implementations are
available.
5. Are better authoritative references possible for STL and PLY? See Mantis
1522 <https://mantis.web3d.org/view.php?id=1522>.
6. The "#*DEFname*" syntax directly matches EXTERNPROTO URL semantics
<https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/concepts.html#EXTERNPROTOURLSemantics>
considerations.
Not requiring IMPORT/EXPORT statements provides greater backwards
compatibility with legacy models, avoiding unnecessary complications and
possible ambiguity.
7. Composition of online addresses and parameter values within a *url* field
offers the possibility of invoking an online server to perform file-format
conversions. See email thread [x3d-public] Inline > type field > for
loading / converting / parsing other content
<https://web3d.org/pipermail/x3d-public_web3d.org/2026-March/022355.html>
for
further discussion. Such additional functionality supports the use cases
under consideration by Metaverse Standards Forum (MSF) 3D Web
Interoperability
<https://metaverse-standards.org/domain-groups/3d-web-interoperability>
Working
Group.
Have fun with X3D extensibility! 😁
all the best, Don
--
X3D Graphics, Maritime Robotics, Distributed Simulation
Relative Motion Consulting https://RelativeMotion.info
On Thu, Apr 9, 2026 at 7:11 PM Don Brutzman <don.brutzman at gmail.com> wrote:
> Not a spec problem. Level 1 is written to provide options for Interchange
> profile, namely minimal support on minimal platforms.
>
> Thanks for checking Joe... Nothing we have to worry about here.
>
> all the best, Don
> --
> X3D Graphics, Maritime Robotics, Distributed Simulation
> Relative Motion Consulting https://RelativeMotion.info
>
>
> On Thu, Apr 9, 2026 at 4:42 PM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
>> OK, so IFS lists two versions of creaseAngle
>>
>>
>>
>> Table 13.2 — Geometry3D component support levels
>> Level 2
>> IndexedFaceSet
>> Core 1
>> Grouping 1
>> Rendering 1
>> Shape 1
>> For creaseAngle, only 0 and π radians supported
>>
>>
>> except:
>>
>> 13.3.6 IndexedFaceSet
>> SFFloat [] creaseAngle 0 [0,∞)
>>
>>
>>
>> and,
>>
>>
>>
>> Table 11.2 — Rendering component support levels
>> IndexedTriangleSet
>> Level 3
>> Core 1
>> Grouping 1
>> All fields fully supported.
>> (No creaseAngle)
>>
>>
>>
>> OK, but IFS creaseAngle technically ends up 0 to pi whatever you put in
>> there,
>>
>> but by experiment it seems to work in that range.
>>
>> and the note should be removed from 13.2 and moved to ITS?
>>
>>
>>
>> Thanks,
>>
>> Joe
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> Table 13.2 — Geometry3D component support levels
>> Level 2
>> IndexedFaceSet
>> Core 1
>> Grouping 1
>> Rendering 1
>> Shape 1
>> For creaseAngle, only 0 and π radians supported
>>
>>
>>
>> Table 11.2 — Rendering component support levels
>> IndexedTriangleSet
>> Level 3
>> Core 1
>> Grouping 1
>>
>>
>>
>> Is this a spec problem?
>>
>> I can be ok with ITS 0 or pi creaseAngle value
>>
>> but I thought IFS could 0 to pi.
>>
>> So use know that
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Don Brutzman <don.brutzman at gmail.com>
>> Sent: Apr 9, 2026 3:33 PM
>> To: Michalis Kamburelis <michalis at castle-engine.io>
>> Cc: Extensible 3D \(X3D\) Graphics public discussion <
>> x3d-public at web3d.org>, <joedwil at earthlink.net>
>> Subject: Re: [x3d-public] InlineGeometry node and PLY format support in
>> Castle Game Engine
>>
>>
>> Good points all in this thread, lots to consider here as we strive for
>> simple effectiveness.
>>
>> Any geometry type might be returned... if there was an <InlineGeometry
>> url="MyExpensiveCadModel.x3d#QuadSetOfInterest"/> it seems likely a QuadSet
>> would be returned.
>>
>> A creaseAngle field might lead to much downstream confusion, even if a
>> satisfactory specification definition was crafted.
>>
>> A much-simpler possible field to express author intent: a 'smooth' field
>> declaring a hint for applying smooth versus sharp shading, if possible.
>>
>> - SFBool [in out] smooth TRUE
>>
>> all the best, Don
>> --
>> X3D Graphics, Maritime Robotics, Distributed Simulation
>> Relative Motion Consulting https://RelativeMotion.info
>>
>> On Thu, Apr 9, 2026 at 2:12 PM Michalis Kamburelis <
>> michalis at castle-engine.io> wrote:
>>
>>> To Don's idea of "creaseAngle as a suggestion":
>>>
>>> I'm not against it (and I would support it in CGE as much as we could :)
>>> ). But as a hint, it could be problematic, as users will find it is not
>>> reliable and could have "wrong expectations".
>>>
>>>
>>> - E.g. X_ITE generates IndexedTriangleSet from PLY mesh, while CGE
>>> generates (right now!) IndexedFaceSet. This means that users could have
>>> wrong expectations from X_ITE -- creaseAngle, for PLY, in X_ITE would not
>>> work.
>>>
>>>
>>>
>>> - ( Unless X_ITE changes algorithm to use IndexedFaceSet. But
>>> forcing this would be bad -- a browser should have a choice what geometry
>>> type to use here, not be forced to use IndexedFaceSet . Which geometry type
>>> is more suitable -> depends on internal optimizations. )
>>>
>>>
>>>
>>> - If CGE changes our algorithm (which I reserve the right to do! we
>>> had in the past occasions when it made sense to change geometry types for
>>> terrains), then suddenly we will have bugreports
>>> "InlineGeometry.createAngle for PLY worked in Castle Model Viewer version
>>> 5, but no longer works in version 6". This will make users unhappy:)
>>> Explaining to users that "InlineGeometry.creaseAngle was always supposed to
>>> be only a hint, never guarantee" will not be of much help -- because users
>>> will then have models that depended on the old behavior, and will consider
>>> the new behavior a regression.
>>>
>>>
>>> Also: browsers should be "consistent by default" anyway. We should to
>>> "what is expected by given format". Which means that, if PLY models are (by
>>> convention) displayed with smooth normals (when no explicit normals are
>>> provided) -> then all viewers, X_ITE and CGE, should display them by
>>> default with smooth normals. (Which is what happens now, after my change
>>> yesterday:) ).
>>>
>>> IOW, I'm not against InlineGeometry.creaseAngle (as long as default
>>> would be "-1" meaning "no override")... but it doesn't achieve that much
>>> (we need to make our defaults consistent anyway), and may in fact give
>>> wrong expectations to users (when it will work only in certain
>>> browsers/versions).
>>>
>>>
>>>
>>> To Joe: I'm afraid making the geometry type depending on profile would
>>> be surprising to users, and would not really solve the issue discussed here
>>> :)
>>>
>>> Both browsers (X_ITE and CGE) support both geometry types
>>> (IndexedTriangleSet and IndexedFaceSet). It's not a question of support.
>>> Both browsers choose to load PLY as most optimal format, which may be a
>>> different decision for each browser. This should not be influenced by
>>> profile of enclosing file, this would be quite non-standard (as the profile
>>> also doesn't influence regular Inline).
>>>
>>> Regards,
>>> Michalis
>>> On Thursday, April 9th, 2026 at 03:09, Don Brutzman via x3d-public <
>>> x3d-public at web3d.org> wrote:
>>>
>>> Please re-read my suggestions from earlier today. Apologies for not
>>> being clearer.
>>>
>>> I was trying to express that creaseAngle might be a hint from the
>>> author, regardless of original inlined geometry mesh type and also
>>> independent of the browsers choice of geometry (IFS, triangles, etc.). It
>>> is a way for author to express whether smooth rendering is desired.
>>>
>>> For example, a literal creaseAngle might be literally unusable if
>>> browser chooses to return a TriangleSet, but the browser might add Normal
>>> values to address smooth/sharp edges.
>>>
>>> all the best, Don
>>> --
>>> X3D Graphics, Maritime Robotics, Distributed Simulation
>>> Relative Motion Consulting https://RelativeMotion.info
>>>
>>> On Wed, Apr 8, 2026 at 5:30 PM Joe D Williams via x3d-public <
>>> x3d-public at web3d.org> wrote:
>>>
>>>> Choice of IFS or ITS could be a choice of Profile.
>>>>
>>>> IFS is simple profile, rendering 1 for IFS and rendering 3 for ITS.
>>>>
>>>> Joe
>>>>
>>>> -----Original Message-----
>>>> From: Michalis Kamburelis via x3d-public <x3d-public at web3d.org>
>>>> Sent: Apr 8, 2026 1:17 PM
>>>> To: Holger Seelig <holger.seelig at yahoo.de>
>>>> Cc: Michalis Kamburelis <michalis at castle-engine.io>, Extensible 3D
>>>> (X3D) Graphics public discussion <x3d-public at web3d.org>
>>>> Subject: Re: [x3d-public] InlineGeometry node and PLY format support in
>>>> Castle Game Engine
>>>>
>>>>
>>>> Hm, good point about the geometry type and so, the creaseAngle not
>>>> being that much useful...
>>>>
>>>> Indeed the difference in look between X_ITE and CGE is then because of
>>>> different geometry choice.
>>>>
>>>>
>>>> - Castle Game Engine converts PLY mesh into IndexedFaceSet, where
>>>> the creaseAngle (default 0, so flat shading) decides the look. I've done it
>>>> because PLY meshes have polygons and we have already handling for
>>>> possibly-concave polygons (which I understand PLY may have) at
>>>> IndexedFaceSet. So we generate PLY -> IndexedFaceSet, set
>>>> IndexedFaceSet.convex=FALSE, and we're done.
>>>>
>>>>
>>>>
>>>> - ( To be clear, this decision is not set in stone. My past
>>>> experience with e.g. terrains showed that sometimes changing the generated
>>>> primitive/geometry type is useful, for unforeseen reasons :) So this is
>>>> _not_ a guarantee that CGE will always read PLY to IndexedFaceSet, and not
>>>> e.g. IndexedTriangleSet. )
>>>>
>>>>
>>>>
>>>> - If X_ITE converts PLY mesh into IndexedTriangleSet, then
>>>> creaseAngle doesn't exist (IndexedTriangleSet.normalPerVertex decides, and
>>>> it's either all flat or all smooth).
>>>>
>>>>
>>>>
>>>>
>>>> Indeed we're not going to reconcile this with creaseAngle.
>>>>
>>>> I think in the end, it comes down to the underlying formats -- is there
>>>> any spec, or just a hint / consensus, how should normals for PLY models be
>>>> generated? Does everyone create smooth meshes then, like X_ITE? If the
>>>> consensus is to generate smooth normals -> then the fix is just on CGE
>>>> side, we can trivially change our PLY -> IndexedFaceSet to set
>>>> creaseAngle>=pi and then CGE and X_ITE will be consistent. Seems like this
>>>> is the simplest way to go :)
>>>>
>>>> Hm, done in
>>>> https://github.com/castle-engine/castle-engine/commit/bbbfc016ed179b2009cf8194dd692b81adf1f6e3
>>>> :) PLY teapot from
>>>> https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/TeapotInlineGeometryPlyIndex.html
>>>> is now smooth in our rendering.
>>>>
>>>> Regards,
>>>> Michalis
>>>>
>>>>
>>>> On Wednesday, April 8th, 2026 at 21:00, Holger Seelig <
>>>> holger.seelig at yahoo.de> wrote:
>>>>
>>>> If the teapot is faceted in Castle, it’s more likely because a
>>>> different geometry was used. X_ITE converts the PLY teapot into an
>>>> IndexedTriangleSet, which, as mentioned earlier, does not have a
>>>> creaseAngle field.
>>>>
>>>> If InlineGeometry has a creaseAngle field, it gives the impression that
>>>> the creaseAngle can be set for the loaded geometry, but this is only
>>>> possible in the rarest of cases.
>>>>
>>>> Best regards,
>>>> Holger
>>>>
>>>> —
>>>> Holger Seelig
>>>> holger.seelig at yahoo.de
>>>>
>>>>
>>>> Am 08.04.2026 um 20:49 schrieb Holger Seelig via x3d-public <
>>>> x3d-public at web3d.org>:
>>>> I would like to point out that only 4 of the 32 X3DGeometryNode's have
>>>> a creaseAngle field. On the other hand, why is creaseAngle preferred here?
>>>> The solid field or ccw can also be useful, but they are not available on
>>>> all X3DGeometryNode's either.
>>>>
>>>> Best regards,
>>>> Holger
>>>>
>>>> —
>>>> Holger Seelig
>>>> holger.seelig at yahoo.de
>>>>
>>>>
>>>> Am 08.04.2026 um 18:13 schrieb Michalis Kamburelis via x3d-public <
>>>> x3d-public at web3d.org>:
>>>> Confirming Don's observations -- the difference in rendering of Teapot
>>>> from PLY in
>>>> https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/TeapotInlineGeometryPlyIndex.html
>>>> seems to come from difference in creaseAngle.
>>>>
>>>> In Castle Game Engine, when we load PLY -> we leave
>>>> "IndexedFaceSet.creaseAngle" at default in X3D, which is 0, which results
>>>> in flat shading (
>>>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/geometry3D.html#IndexedFaceSet
>>>> ).
>>>>
>>>> Note that PLY files _can_ provide their own, explicit normal vectors.
>>>> In which case there would be non inconsistency. But, well, this PLY model (
>>>> https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/teapot.ply
>>>> ) does not provide normals. It only has vertex positions.
>>>>
>>>> Introducing "InlineGeometry.creaseAngle" makes sense to me.
>>>>
>>>> Internally, I would also allow loading options as URL anchor, so one
>>>> could load "xxx.ply#crease-angle=123" thus it would be possible to
>>>> influence creaseAngle also for models loaded through "Inline", like
>>>> """Inline { url "model.ply#crease-angle=123" />"""
>>>>
>>>> Compared to Don prose, I would say to allow an option to _don't change
>>>> the underlying value (or browser default)_. Because when we inline e.g. X3D
>>>> geometry, then (possibly) it already has a useful creaseAngle? So I would
>>>> define it like:
>>>>
>>>> """
>>>> InlineGeometry {
>>>> ...
>>>> creaseAngle initializeOnly -1
>>>> }
>>>>
>>>> creaseAngle determines the the automatic calculation of normal vectors
>>>> for the imported geometry. It is only used if all of the below are true:
>>>>
>>>> 1. Given creaseAngle is >= 0. The default, -1, means to use
>>>> creaseAngle specified in the imported model (if the format of it allows
>>>> creaseAngle, like X3D allows) or browser-specific default.
>>>> 2. Imported geometry results in X3D geometry with creaseAngle, e.g.
>>>> in IndexedFaceSet. For other geometry types, like PointSet, creaseAngle is
>>>> ignored.
>>>> 3. Imported geometry doesn't have explicit normal values. E.g. if
>>>> PLY file has explicit normal provided, then these are used, and the
>>>> creaseAngle value doesn't matter.
>>>>
>>>>
>>>> """
>>>>
>>>> Regards,
>>>> Michalis
>>>>
>>>>
>>>> On Tuesday, April 7th, 2026 at 23:52, Don Brutzman <
>>>> don.brutzman at gmail.com> wrote:
>>>>
>>>> Thanks for references Michalis. Here is an example test scene.
>>>>
>>>> - X3D Example Archives: X3D4AM, X3D for Advanced Modeling, Additive
>>>> Manufacturing, Teapot Inline Geometry Ply
>>>> - Loading a classic teapot model in PLY format
>>>> -
>>>> https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/TeapotInlineGeometryPlyIndex.html
>>>>
>>>> Implementation and evaluation always helps... Note significant
>>>> differences in rendering due to implicit choices for *creaseAngle*:
>>>>
>>>> -
>>>> https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/TeapotInlineGeometryPlyCastle.png
>>>> -
>>>> https://www.web3d.org/x3d/content/examples/X3dForAdvancedModeling/AdditiveManufacturing/TeapotInlineGeometryPlySunrize.png
>>>> <image.png> <image.png>
>>>>
>>>> Currently the author has no settings to adjust the handling of the mesh.
>>>>
>>>> Suggestion: might we consider adding creaseAngle as a field for
>>>> InlineGeometry node? It is defined in the specification as follows.
>>>>
>>>> - X3D Architecture 4.1 draft — ISO/IEC 19775-1:202x — 11 Rendering
>>>> component
>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/rendering.html#CommonGeometryFields> 11.2.3
>>>> Common geometry fields
>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/rendering.html#CommonGeometryFields>
>>>> -
>>>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/rendering.html#CommonGeometryFields
>>>>
>>>> The *creaseAngle* field affects how default normals are generated. If
>>>>> the angle between the geometric normals of two adjacent faces is less than
>>>>> the crease angle, normals shall be calculated so that the faces are shaded
>>>>> smoothly across the edge; otherwise, normals shall be calculated so that a
>>>>> lighting discontinuity across the edge is produced. Crease angles shall be
>>>>> greater than or equal to 0.0 angle base units.
>>>>
>>>> EXAMPLE A crease angle of 0.5 angle base units means that an edge
>>>>> between two adjacent polygonal faces will be smooth shaded if the geometric
>>>>> normals of the two faces form an angle that is less than 0.5 angle base
>>>>> units. Otherwise, the faces will appear faceted.
>>>>
>>>>
>>>> However, typically an author has no idea on what might be an
>>>> appropriate value, unless they do extensive sleuthing on an unchanging
>>>> piece of geometry. Thus we might pick a default value for *creaseAngle*
>>>> field that always results in smooth shading.
>>>>
>>>> - SFFloat [ ] creaseAngle 3.14159 [0,+inf)
>>>>
>>>> Further descriptions found in X3D tooltips.
>>>>
>>>> - X3D Tooltips in English version 4.0 (with X3D version 4.1 draft),
>>>> IndexedFaceSet.creaseAngle
>>>> <https://www.web3d.org/x3d/tooltips/X3dTooltips.html#IndexedFaceSet.creaseAngle>
>>>> -
>>>> https://www.web3d.org/x3d/tooltips/X3dTooltips.html#IndexedFaceSet.creaseAngle
>>>>
>>>> *[creaseAngle accessType initializeOnly
>>>> <https://www.web3d.org/x3d/tooltips/X3dTooltips.html#accessType>, type
>>>> SFFloat <https://www.web3d.org/x3d/tooltips/X3dTooltips.html#SFFloat> CDATA
>>>> <https://www.web3d.org/x3d/tooltips/X3dTooltips.html#CDATA> "0"] [0,+∞)
>>>> <https://www.web3d.org/x3d/tooltips/X3dTooltips.html#RangeIntervals>*
>>>> creaseAngle defines angle (in radians) for determining whether adjacent
>>>> polygons are drawn with sharp edges or smooth shading. If angle between
>>>> normals of two adjacent polygons is less than creaseAngle, smooth shading
>>>> is rendered across the shared line segment.
>>>> *Hint:* in Interchange profile only 0 and π radians supported.
>>>> *Hint:* creaseAngle=0 means render all edges sharply,
>>>> creaseAngle=3.14159 means render all edges smoothly.
>>>> *Hint:* radian units for angular measure
>>>> https://en.wikipedia.org/wiki/Radian
>>>> all the best, Don
>>>> --
>>>> X3D Graphics, Maritime Robotics, Distributed Simulation
>>>> Relative Motion Consulting https://RelativeMotion.info
>>>> <https://relativemotion.info/>
>>>>
>>>> On Mon, Apr 6, 2026 at 5:26 PM Michalis Kamburelis <
>>>> michalis at castle-engine.io> wrote:
>>>>
>>>>> As for black points reported by John in some PLY files: Fixed.
>>>>>
>>>>> I added to Castle Game Engine / Castle Model Viewer support for
>>>>> reading color values from PLY through alternative properties. Details and
>>>>> links to more explanation in commit
>>>>> https://github.com/castle-engine/castle-engine/commit/c6d9acc08aa7a20e991b140d1379e265ea496faf
>>>>> . Screenshot attached.
>>>>>
>>>>> Note: All this is doing is adding alternative way to read colors from
>>>>> PLY, which lands in X3D per-vertex colors (Color or ColorRGBA node).
>>>>>
>>>>> I'm not entering the Gaussian Splat discussion in related thread(s)
>>>>> :), as I have to educate myself better about Gaussian Splats first.
>>>>> Tomorrow's Khronos lecture seems like a good opportunity to start learning.
>>>>>
>>>>> Regards,
>>>>> Michalis
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Monday, April 6th, 2026 at 20:49, John Carlson via x3d-public <
>>>>> x3d-public at web3d.org> wrote:
>>>>>
>>>>> Sorry I meant I was able to see black point clouds without color
>>>>> (Michalis apparently uses different properties?).
>>>>> On Mon, Apr 6, 2026 at 1:00 PM John Carlson <yottzumm at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> I agree that the PLYs that I worked with weren’t suitable for X3D.
>>>>>> Either my parser was off, or there were negative color values, negative
>>>>>> scales etc. I thought a second person could look at the same files and make
>>>>>> better progress. I was able to view black points clouds (no clouds) from
>>>>>> the PLY files in castle. I can probably change the property in the PLY file
>>>>>> to achieve color in the point cloud. The point is, I don’t know if there’s
>>>>>> standard PLY color properties.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> John
>>>>>>
>>>>>> On Mon, Apr 6, 2026 at 12:18 AM Don Brutzman <don.brutzman at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Thank you Michalis for implementing the draft InlineGeometry node.
>>>>>>> Having both Castle Game Engine and (already supporting)
>>>>>>> X_ITE/Playground/Sunrize is definitely accelerating our design,
>>>>>>> implementation and evaluation of LOA-5 bone segments for HAnim. Tests of
>>>>>>> your Castle Model Viewer beta release look good on this end.
>>>>>>>
>>>>>>> Repeating a prior reply: "Gaussian Splat PLYs" (whatever that means)
>>>>>>> does not seem like a good use of effort. There is a lot of ongoing
>>>>>>> developmental work on gaussian splat formats by various companies that are
>>>>>>> nonstandard, inconsistent, possibly unstable, and often proprietary. Some
>>>>>>> happen to use .ply as a container. A prudent approach is to wait and see
>>>>>>> what glTF does once things stabilize. Using Inline with glTF 2.0 (in json
>>>>>>> or glb) is already in X3D 4.0, extension support by browsers is optional,
>>>>>>> so that is a reasonable future path if consensus ever emerges.
>>>>>>>
>>>>>>> The draft X3D specification for InlineGeometry describes rationale
>>>>>>> and includes references for the PLY format.
>>>>>>>
>>>>>>> - X3D Architecture 4.1 draft — ISO/IEC 19775-1:202x — 9
>>>>>>> Networking component
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/networking.html#InlineGeometry> 9.4.3
>>>>>>> InlineGeometry
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/networking.html#InlineGeometry>
>>>>>>> -
>>>>>>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/networking.html#InlineGeometry 9.4.3
>>>>>>> InlineGeometry
>>>>>>>
>>>>>>> InlineGeometry : X3DGeometryNode, X3DUrlObject {
>>>>>>> SFTime [in,out] autoRefresh 0.0 [0,infinity)
>>>>>>> SFTime [in,out] autoRefreshTimeLimit 3600.0 [0,infinity)
>>>>>>> SFString [in,out] description ""
>>>>>>> SFBool [in,out] load TRUE
>>>>>>> SFNode [in,out] metadata NULL [X3DMetadataObject]
>>>>>>> MFString [in,out] url [] [URI]
>>>>>>> }
>>>>>>>
>>>>>>> InlineGeometry loads geometry from an external file. The result
>>>>>>> provides a polygonal mesh, set of lines, point cloud, parametric surface,
>>>>>>> or other geometry.
>>>>>>>
>>>>>>> The *url* field can support loading a variety of file formats
>>>>>>> defining polygonal mesh geometry. When the *url* field contains
>>>>>>> no values ([]), no default geometry is provided. Required
>>>>>>> Recommended support by X3D browsers includes both ASCII and
>>>>>>> binary encodings for the STL format (see STL
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/bibliography.html#STL>)
>>>>>>> as well as the PLY polygonal geometry format (see PLY
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/bibliography.html#PLY>),
>>>>>>> respectively. Other file types can be optionally supported by a browser.
>>>>>>> TODO: consider "required support" of STL/PLY formats rather than
>>>>>>> "recommended support" since numerous open-source conversion implementations
>>>>>>> are available, no IPR considerations pertain, and STL/PLY formats are the
>>>>>>> primary use case.
>>>>>>>
>>>>>>> If the *url* field refers to an X3D file or a VRML97 file, the
>>>>>>> first geometry node found in that file (excluding both prototype
>>>>>>> declarations and prototype instances) is used to provide the InlineGeometry
>>>>>>> contents. X3D browsers shall recognize *url* fields that end
>>>>>>> with "#*DEFname*" to mean the geometry node with DEF label of
>>>>>>> *DEFname* in the given X3D or VRML97 file.
>>>>>>>
>>>>>>> The run-time system can support any number of 3D model resource
>>>>>>> types as long as those follow the available Model Primary Content Type for
>>>>>>> Multipurpose Internet Mail Extensions (MIME) model definition (see
>>>>>>> RFC2077
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/references.html#RFC2077>),
>>>>>>> provide a registered content type (e.g., model/stl, text/plain etc.) (see
>>>>>>> IANA_MEDIA
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/references.html#IANA_MEDIA>
>>>>>>> and IANA_STL
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/references.html#IANA_STL>),
>>>>>>> and can be determined with some form of content negotiation (see
>>>>>>> RFC9110
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/references.html#RFC9110>).
>>>>>>> Support is recommended for both text and binary encodings associated with a
>>>>>>> given model format, when so defined.
>>>>>>>
>>>>>>> NOTE Experimental variations of PLY format used for Gaussian
>>>>>>> Splat rendering are not expected for InlineGeometry. Such capabilities are
>>>>>>> better supported by Inline node loading of glTF models.
>>>>>>>
>>>>>>> EXAMPLES
>>>>>>>
>>>>>>> Shape {
>>>>>>> geometry InlineGeometry { url [ "MyFavoriteMesh.stl" ] }
>>>>>>>
>>>>>>> appearance USE FancyPaintAppearance # previously defined
>>>>>>> }
>>>>>>>
>>>>>>> Shape {
>>>>>>> geometry InlineGeometry { url [ "HelloWorld.x3d#TextMessage" ] }
>>>>>>>
>>>>>>> appearance USE FancyPaintAppearance # previously defined
>>>>>>> }
>>>>>>>
>>>>>>> Editors notes.
>>>>>>> - Are better authoritative references possible for STL and PLY?
>>>>>>> See Mantis 1522 <https://mantis.web3d.org/view.php?id=1522>.
>>>>>>> - InlineGeometry results differ from an Inline node, which
>>>>>>> produces an X3DChildNode scene subgraph implementing the X3DBoundedObject
>>>>>>> interface. An Inline node cannot be used as the *geometry*
>>>>>>> field of a Shape.
>>>>>>> - Results from browser loading may be any kind of polygonal
>>>>>>> mesh or parametric surface (e.g. IndexedFaceSet, TriangleSet, Extrusion,
>>>>>>> etc.) but cannot be further manipulated or animated by events from the
>>>>>>> scene.
>>>>>>> - Direct loading of such geometry files eliminates the need
>>>>>>> for prior model conversion into X3D, and adds flexibility when applying
>>>>>>> Appearance to the result.
>>>>>>> - The "#*DEFname*" syntax directly matches EXTERNPROTO URL
>>>>>>> semantics
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/concepts.html#EXTERNPROTOURLSemantics>
>>>>>>> considerations. Not requiring IMPORT/EXPORT statements provides greater
>>>>>>> backwards compatibility with legacy models, avoiding unnecessary
>>>>>>> complications and possible ambiguity.
>>>>>>> - Composition of online addresses and parameter values within
>>>>>>> a *url* field offers the possibility of invoking an online
>>>>>>> server to perform file-format conversions. See email thread [x3d-public]
>>>>>>> Inline > type field > for loading / converting / parsing other content
>>>>>>> <https://web3d.org/pipermail/x3d-public_web3d.org/2026-March/022355.html>
>>>>>>> for further discussion. Such additional functionality supports the use
>>>>>>> cases under consideration by Metaverse Standards Forum (MSF) 3D
>>>>>>> Web Interoperability
>>>>>>> <https://metaverse-standards.org/domain-groups/3d-web-interoperability>
>>>>>>> Working Group.
>>>>>>>
>>>>>>>
>>>>>>> Worth reading: the original PLY definition first defined in 1994 by
>>>>>>> Greg Turk at Stanford University., references above.
>>>>>>>
>>>>>>> - [PLY
>>>>>>> <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/bibliography.html#PLY>
>>>>>>> ]
>>>>>>> -
>>>>>>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/bibliography.html#PLY
>>>>>>> - Wikipedia, PLY (file format), 26 February 2026.
>>>>>>> https://en.wikipedia.org/wiki/PLY_(file_format)
>>>>>>>
>>>>>>> and
>>>>>>>
>>>>>>> 1. Greg Turk. "The PLY Polygon File Format"
>>>>>>> <https://web.archive.org/web/20161204152348/http://www.dcs.ed.ac.uk/teaching/cs4/www/graphics/Web/ply.html>.
>>>>>>> Archived from the original
>>>>>>> <http://www.dcs.ed.ac.uk/teaching/cs4/www/graphics/Web/ply.html>
>>>>>>> on 2016-12-04.
>>>>>>> 2. Greg Turk. "The PLY Polygon File Format (extended)"
>>>>>>> <https://gamma.cs.unc.edu/POWERPLANT/papers/ply.pdf> (PDF).
>>>>>>>
>>>>>>> and
>>>>>>>
>>>>>>> - PLY - Polygon File Format
>>>>>>> <https://paulbourke.net/dataformats/ply/>
>>>>>>> https://paulbourke.net/dataformats/ply
>>>>>>>
>>>>>>> Improvements to draft specification, especially with implementation
>>>>>>> and evaluation, are always welcome.
>>>>>>> all the best, Don
>>>>>>> --
>>>>>>> X3D Graphics, Maritime Robotics, Distributed Simulation
>>>>>>> Relative Motion Consulting https://RelativeMotion.info
>>>>>>> <https://relativemotion.info/>
>>>>>>>
>>>>>>> On Sun, Apr 5, 2026 at 6:39 PM John Carlson via x3d-public <
>>>>>>> x3d-public at web3d.org> wrote:
>>>>>>>
>>>>>>>> Hi, Michalis, Seeing Gaussian Splat PLYs renderered with humanoid
>>>>>>>> animation would be cool to see. With your expertise in binary formats and
>>>>>>>> binary PLY, probably an easy next step!
>>>>>>>>
>>>>>>>> John
>>>>>>>>
>>>>>>>> On Sun, Apr 5, 2026 at 8:05 PM Michalis Kamburelis via x3d-public <
>>>>>>>> x3d-public at web3d.org> wrote:
>>>>>>>>
>>>>>>>>> With big thanks to Don who provided information and pushed me to
>>>>>>>>> implement it!:)
>>>>>>>>>
>>>>>>>>> 1. We support now InlineGeometry in Castle Game Engine and Castle
>>>>>>>>> Model Viewer.
>>>>>>>>>
>>>>>>>>> - I tested on a few examples, and made our own:
>>>>>>>>> https://github.com/castle-engine/demo-models/tree/master/x3d/inline_geometry
>>>>>>>>>
>>>>>>>>> - You can refer to a geometry from any model format we support,
>>>>>>>>> including X3D, glTF, STL, PLY...:
>>>>>>>>> https://castle-engine.io/model_formats
>>>>>>>>>
>>>>>>>>> 2. We support now loading models in a PLY format.
>>>>>>>>>
>>>>>>>>> - ASCII and binary versions.
>>>>>>>>>
>>>>>>>>> - Faces or without faces (point cloud, i.e. just our PointSet).
>>>>>>>>>
>>>>>>>>> - Testcases include
>>>>>>>>> https://github.com/castle-engine/demo-models/tree/master/ply and
>>>>>>>>> https://sketchfab.com/3d-models/kaktus-ply-7b7cc7188f17468595506500e186a9c0
>>>>>>>>> .
>>>>>>>>>
>>>>>>>>> More information and screenshots about both features in our news
>>>>>>>>> post on
>>>>>>>>> https://castle-engine.io/wp/2026/04/06/support-for-ply-model-format-and-inlinegeometry-node/
>>>>>>>>> .
>>>>>>>>>
>>>>>>>>> They are available to test right now if you download
>>>>>>>>> - the "snapshot" version of Castle Model Viewer
>>>>>>>>> https://castle-engine.io/castle-model-viewer
>>>>>>>>> - or full engine from https://castle-engine.io/download .
>>>>>>>>>
>>>>>>>>> Regards,
>>>>>>>>> Michalis
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> x3d-public mailing list
>>>>>>>>> x3d-public at web3d.org
>>>>>>>>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>>>>>>>>
>>>>>>>> _______________________________________________
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>>
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