Trbvh builder causes exception


When using the Trbvh builder for my geometry I get an exception saying the following:

Unknown error (Details: Function “_rtContextLaunch1D” caught exception: Encountered a CUDA error: [15467213] returned (4): unspecified launch failure, [15270146])

However if I use Sbvh or MedianBvh instead everything works like a charm, but slow.

I use a GeForce 740M. Any thoughts on this please?

While we’re on the topic, is it faster to use a Trbvh than a MedianBvh on dynamic 40 k triangle meshes?

Trbvh should build faster than all other builders, except maybe Lbvh. But the Trbvh acceleration structure will render (traverse) faster than Lbvh.
Trbvh needs a lot of memory temporarily! If that doesn’t work, try Lbvh for dynamic geometry as well if acceleration structure building time is more important than rendering time.

What’s your system configuration?
OS version, OS bitness, installed GPUs (is answered) , display driver version, OptiX version (required to decode the error message), CUDA toolkit version.
If that fails on the newest available versions, a reproducer would be needed to investigate.


I tried Lbvh but it’s slow rendering performance makes it slower overall. Right now MedianBvh gives the best performance.

I have installed windows 7, 32 bit, GeForce 740 M, driver version 337.88, Optix version 3.5.1, CUDA 6.0 (I guess).

OptiX 3.5.1 only supports up to CUDA 5.5.
Do a “set c” on the command prompt to see which CUDA environment variables are set.

Please try again with OptiX 3.6.0.
It’s on the same location you got when registering for OptiX 3.5.
OptiX 3.6.0 supports CUDA 6.0 and also contains some fixes around Trbvh.

I tried with Optix 3.6.0 and the video driver crashed.

Crashed as in the driver was incompatible with OptiX 3.6.0, or crashed as in you encountered TDR? If the latter, there are many posts on this message board about how to resolve that.

The latest video driver I use (337.88) is compatible with OptiX 3.6.0. It runs fine my application with a MedianBvh builder, but when I change to Trbvh it crashes the driver. Are you suggesting it’s taking too much time to build and it’s forced to quit?



I have now installed Windows 7 Ultimate, 64 bit, GeForce 740 M, driver version 337.88, Optix version 3.6, CUDA 6.0 and it still crashed when using Trbvh. The MedianBvh builder is a bit slow and it takes about 30 ms to build on my scene.

How much faster in build times is Trbvh compared to MedianBvh?

If MedianBvh only takes 30ms it sounds like you have a small scene. I wouldn’t expect a huge speedup from Trbvh. But how many rays you’ll be tracing also matters. If it’s a lot, it may be worth using Trbvh, since the ray tracing is much faster than for MedianBvh.

This bug may be fixed in OptiX 3.6.3. Please try again, if you would. And if it still fails, mail and we’ll debug it.