Ctrl.Occlusion makes XSI crash

[shushens]

Hey guys! I am using Ctrl.Occlusion shader 1.6 on Softimage 7.5. I have two AO passes for a car. In one, I am showing AO between parts of the car and in the other, between the car and the ground. I am partitioning with white constant shader.

When I am doing the AO between car and ground, it happens just fine. When I do it with just the car, it says:

PHEN 0.11 warn: shadow shader "ctrl_occlusion" illegally called "mi_trace_transparent". Shadow rays aborted!

I am also getting the same warning against PHEN 0.4, 0.6 and 0.9.

After rendering 30-40% of the image, the preview window just freezes and XSI stops responding. Every time the render is stopping at exactly the same place.

I am not sure why this is happening. I get rid of the car and just do it with a grid and a sphere and it works just fine. I am using the following settings for the shader:

angle 60
far plane 16
gamma 0.7
gain 0.2

Everything else is default.

Any idea why this might be happening? I am using the direction of Physical Sun and direction blend 0.9. FG support is turned off.

[Rork]

Are you sure that shader is still working properly for 7.5? It's a tad old and the error message suggests it's doing something in MR that's not working properly (anymore).
Do you really need the ctrl version, or can you just do the AO with the built in shader in XSI. Did you try to see if that one crashes as well??

rob

[shushens]

Thanks for the response!

I thought Ctrl.Occlusion is the only one that takes lights into consideration. Yeah it surely does act jumpy and sometimes behaves rather odd, but still it does get the job done most of the time. I did solve the problem temporarily by putting a point light at the root of the Physical Sun, setting its intensity to 0 and adding that one to the shader instead of the Physical Sun. Should not give 100% identical result, but it cooks ultimately.

Is there a smarter way to drive occlusion by light direction?

[origin]

I think puppet megatk has occlusion with vector/blend support.

[Rork]

Ah, I did forget about this thread, but I can recall a way to pipe lights into the occlusion, I think it had to do with smartly linking some vector nodes. I'm pretty sure there were some threads on XSIBase on this. I can't recall the proper method used, and I don't have the time atm to fiddle and test.

You might give it a try, it's lurking somewhere in the XSIBase dungeons

rob