Hello everybody!

Concerning the graphical 3D rendering I have a problem with the (very low) frame rates of H3D. I downloaded the H3DAPI 2.1.1 Source Code and created a 32-bit release built by using MS Visual Studio 2010. When I started the H3DViewer application on my laptop (Lenovo ThinkPad T520, NVIDIA NVS 4200M, Windows 7 Professional 64 bit with SP1) and opened a x3d-file of about 8 MB containing simplified CAD data, I realized that the frame rate of the graphical rendering was very low (about 5 frames per second). Other x3D viewer (e.g. freeWRL) are able to render the same x3d-file on my machine with a significantly higher frame rate (smooth and fluent rendering).

By means of a monitoring tool (GPU shark) I observed that H3D produces a constant usage load of 99% on the graphics card. This usage load does not depend on the user interaction or on the movement of the 3D objects displayed. This seems to be an unnatural and counterintuitive behaviour for a rendering engine. A significant load on the graphics card is supposed to occur only when the 3D objects perform nontrivial movements.

Could somebody please give me a hint whether it is possible to increase the frame rate of H3D. (Changing to a 64-bit built might alleviate the problem, but it would definitely not solve it.)

Thank you for your help in advance.

Heribert Mühlberger (Marvin66)
86199 Augsburg (Germany)

Hello Heribert,

Whether it is possible to increase the framerate of the scene so it is better than other X3D viewers I can not say, it can very well depend on the type of scene.

However, there should be a couple of setting you can change/edit in order to make the rendering in H3D go faster. Again this might depend on the scene. The first step I would urge you to do however is to try the latest trunk of H3D since H3DAPI 2.1.1 is so old, the settings I will talk about further down might not even exist in the latest release. I am really sorry that we have not made a release earlier but we have had to prioritize other work for waaaay to long.

So here are some tips that might increase framerate.
1. Update to latest trunk.
2. Try H3DLoad, to see if there are some settings in H3DViewer that has been changed that slows scene down.
3. Shut off avatar collision, perhaps collision calculations are slow for some reason. It should not do that too much if meshes in scene do not change.
4. Tinker with GraphicsCachingOptions settings(GraphicsOptions in latest trunk). Specifically try to shut off caching just to see if it makes matters even worse or not. Also try the preferVertexBufferObject and the frustumCullingMode fields.
5. Spheres are a big slow-down because of how they are rendered, so if you have any spheres in your scene that might actually slow things down. The preferVertexBufferObject flag means a faster rendering for spheres (in trunk at least). I thought I had implemented normal vertex arrays as well for spheres but apparently I had not. If there are no vertex buffer objects for spheres in the scene try to remove them and then see if you have a big difference or not.
6. IndexedFaceSet can render slow in H3DAPI. Try IndexedTriangleSet. The reason for slow rendering is that no vertex arrays/ vertex buffer objects are used. A theoretical speedup for non-changing IndexedFaceSets could be to check if the faces are triangles and in that case use vertex arrays or vertex buffer objects.
7. Various haptics settings can affect graphics rendering speed, but since you are not using haptics I guess this suggestion is moot.


Did you observe the graphics card load (99%) for other scenes as well? That is something we would have to test more throughly. Which tool did you use for GPU testing? There are quite a few.

Marked as spammer.

Dear Markus,

I apologize for not having replied to your posting earlier. I'm a little bit snowed under with work.

Thank you very much for your competent explanations, which were of great benefit to me. It turned out that bullet #6 caused the lion's share of the performance issue. The freeware tool which I used for transforming STEP-CAD-data into x3d-data makes excessive use of IndexedFaceSet-nodes regardless of the fact that all the faces in my file are actually triangles. A simple substitution (IndexedFaceSet-->IndexedTriangleSet) solved the issue and increased the frame rate from 5 frames/sec to about 25 frames/sec (which is OK for me). The graphics card load is now approximately 30% (measured with GPU Shark v0.6.3).

Thank you once more for your help.

Heribert Mühlberger