[x3d-public] Blender unoptimizations

Tue Aug 27 11:14:28 PDT 2024

I believe the below may have been done on import/export from Blender when
hierarchy is unselected.  Instead of the that, in the loader, I am creating
a mirror hierarchy in Blender, as much as is feasible.

On Tue, Aug 27, 2024 at 5:20 AM Holger Seelig via x3d-public <
x3d-public at web3d.org> wrote:

> With the current version of X_ITE (v10.4.1) I have now implemented exactly
> what was suggested here by Andreas. A StaticGroup node will now completely
> remove all transformations and bake them into the geometry. Furthermore,
> assuming the Appearance node is exactly the same (cloned) and the geometry
> nodes are compatible, the geometry nodes will be merged into a single one.
>
> This works very well with all geometry types (point, line, 2D, 3D).
>
> A basic test file is also available. This test file will create 10 static
> nodes from the previous 22 nodes:
>
> https://create3000.github.io/x_ite/playground/?url=https://create3000.github.io/Library/Tests/Components/Grouping/StaticGroup.x3d
>
> Another test file using an Inline node with a glTF sample (1.5 million
> triangles). This test file will create 15 static nodes from the previous 49
> nodes:
>
> https://create3000.github.io/x_ite/playground/?url=https://create3000.github.io/Library/Tests/Components/Grouping/StaticGroupWithInline.x3d
>
> Best regards,
> Holger
>
> --
> Holger Seelig
> Leipzig, Germany
>
> holger.seelig at yahoo.de
> https://create3000.github.io/x_ite/
>
> Am 16.08.2024 um 17:59 schrieb Holger Seelig <holger.seelig at yahoo.de>:
>
> Thank you Andreas for this idea. It is an interesting possibility for
> optimizing geometries. There is nothing like this built into X_ITE yet, but
> there are already optimizations for StaticGroup and if I were to build
> something like this (geometry merge), it would be in StaticGroup, as it
> seems very easy to implement there at first glance.
>
> Best regards,
> Holger
>
> --
> Holger Seelig
> Leipzig, Germany
>
> holger.seelig at yahoo.de
> https://create3000.github.io/x_ite/
>
> Am 15.08.2024 um 16:05 schrieb Michalis Kamburelis via x3d-public <
> x3d-public at web3d.org>:
>
> Castle Game Engine can be told to do this at run-time, it's called
> DynamicBatching.
>
> It's just a checkbox really, see
>
> https://castle-engine.io/apidoc/html/CastleViewport.TCastleViewport.html#DynamicBatching
> . In Castle Model Viewer you can activate it with "View -> Dynamic
> Batching".
>
> Doing it at run-time has naturally benefits and drawbacks:
>
> - The benefit of doing it at run-time is that we can "glue" any
> shapes, not necessarily within StaticGroup.
>
>    We even work "cross-scene", that is in Castle Game Engine you
> typically display multiple models (X3D, glTF, etc.) in your viewport
> and we can "glue" into one shapes from various scenes. See e.g. news
> on
> https://castle-engine.io/wp/2023/06/30/big-renderer-improvements-correct-and-automatic-blending-sorting-more-powerful-batching-now-cross-scene-easier-and-more-reliable-occlusion-culling-and-occlusion-sorting/
> when we introduced "cross-scene" batching.
>
>    Doing it at run-time also means we can do it after frustum culling
> has eliminated shapes outside of frustum. So by "gluing many shapes
> into one" we don't negate the benefits of frustum culling.
>
> - The drawback is that effectively DynamicBatching does some
> additional comparisons and processing at run-time. This consumes time,
> and can (in theory) defeat the gains of batching. But it practice it
> (almost) never happens -- the comparisons are rather fast.
>
> Sometimes it's a huge huge gain. As you say, in some models there's a
> big opportunity to effectively have 1 draw call instead of thousands
> -- which translates to big performance gains. And sometimes it's zero
> gain. I haven't found a case when it's "negative gain", that is when
> the extra work at run-time done comparing / merging actually
> outweights the benefits, but I'm sure it exists (I can construct an
> artificial example of this in my head, but does it happen in real-life
> usage?).
>
> All in all, this is a significant feature with some maintenance costs,
> but it is worth it (on *some* cases).
>
> We plan to introduce also StaticBatching to do it at load time. For
> this we plan to invent a way to tell "this model in completely static"
> -- we don't want to rely on X3D StaticGroup nodes, because
>
> - Many X3D models don't use them (even when it would make sense). It
> requires authoring tools support also (e.g. Blender -> X3D exporter to
> honor some "static" setting from Blender).
>
> - And other 3D formats (like glTF) don't have a StaticGroup equivalent.
>
> So we plan to instead have a "Static" checkbox at TCastleScene
> component ( https://castle-engine.io/viewport_and_scenes ).
>
> The implementation contains hardcoded a number of rules / comparisons
> (to compare and merge things that are important visually, and ignore
> everything else). See
>
> https://github.com/castle-engine/castle-engine/blob/master/src/scene/castleinternalbatchshapes.pas
> . It's of course not perfect, right now it doesn't merge *everything*
> possible. It is coded carefully, i.e. we're not sure can 2 shapes be
> merged -> we don't merge (possibly losing performance, but not risking
> rendering bugs).
>
> To compare, Unity also has both static and dynamic batching. They
> probably don't use X3D underneath :), but still the concept underneath
> is likely similar to what CGE is doing and to what you describe. They
> also have a checkbox "Static" at GameObjects, to help with this.
>
> Regards,
> Michalis
>
> wt., 13 sie 2024 o 23:12 Andreas Plesch via x3d-public
> <x3d-public at web3d.org> napisał(a):
>
>
> I think there may be an opportunity for some relatively simple tools
> to achieve meaningful rendering improvements using the declarative
> nature of X3D.
>
> The idea is that it is much more efficient for (at least for GL based)
> rendering to send a single draw call with a large object compared to
> many draw calls with smaller objects. In effect, if it is possible to
> combine multiple Shapes into a single larger Shape, it can have huge
> effects on rendering speeds. For example, it is possible to easily
> render hundreds of thousands of points in a single cloud while it may
> be nearly impossible to render hundreds of thousands of Shapes with a
> few points each.
>
> StaticGroup is designed to help a browser with such optimizations and
> I was wondering if there are existing tools which already do this,
> perhaps in a preprocessing step.
>
> The simplest, while useful tool I can think of is this:
>
> Inside a StaticGroup, it should be possible to identify Shapes which
> use the same Appearance (by DEF/USE). We group these Shapes by the
> drawing primitive they would use (points, lines, triangles). Combining
> the geometries into a single geometry would be most involved but only
> considering IndexedFace and TriangleSets should be already useful.
> Transforms and TextureTransforms would need to be flattened but this
> can be neatly separated. Finally, a single Shape with the shared
> Appearance and the combined geometry can replace multiple Shapes.
>
> The underlying reason for such a tool is that (machine and human)
> generators and editors tend to produce many Shapes because it is a bit
> harder to keep track of them and organize them into single, larger
> objects.
>
> So any thoughts or pointers to existing X3D optimization tools will be
> very welcome,
>
> Andreas
>
> --
> Andreas Plesch
> Waltham, MA 02453
>
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