So i am starting a new animation project with a group of students at the university of texas at dallas. I am currently trying to integrate houdini, maya, renderman, nuke, boujou, vegas all into one beautiful animation. Most everything is going well. but i keep running into weird problems regarding rman shaders and houdini. And it is totally because i am pretty ignorant of th subtlties they provide.

Regardless, i was wondering if someone could clue me into how rman ambient occlusion works in houdini. I understand how to build the suface shader. but i am not sure how to build the light shader and force rman to ray trace.

Any ideas?

thanks in advance tony

I had the same issue till i found the link, that explained me on how to go about that.
Unfortunatly i don't remember the link.
But it's pretty simple.
What you really have to do, if you know Renderman and Slim, then it's quite easy.
In Slim, you have to create your ambient occlusion shader, then with command rmands -l yourShader.sl yourShader.olt is to execute in Houdini folder, where rmands is Houdini converter.
What will happen, it will create it's own format, to read in houdini renderman's shader.
Basicly you install that shader via install library in Houdini, your shader will be available in Vop.
Plus, don't forget to enable raytrace on your Sop geometry for deffuse.
I usually build my shaders in Slim, cuz it's quite visual, then compile them into SL format and done!
Hope That helps.

Hi there,

You'll find a lot of info about ambient occlusion in PrMan and Mantra if you just search this forum - or if you search http://forums.odforce.net [forums.odforce.net]

Good luck,
Jason

Xcomb,

Genious! I forgot about turning on raytracing through the sop(been using too many different programs lately, stupid maya).

I will give this a whirl a let you know what happens

tony

Hmm what's wrong with Maya?
I use it for many years, and frankly i love it, plus Houdini is great, but lots of stuff i can do same in Maya.

Nothing's wrong with maya, i just got to used to it. Maya and Houdini are really different. So i got ambient occlusion working. I slim all i did was create a matte shader with an occlusion node attached to the matte shaders diffuse illumination. I had some problems with rmands though. I created an otl but in houdini the shader throws lots of 31004 not a parameter of shader. I set the parameters to external in slim, but i am not sure what else to do.

Thanks again for you help.

tony

I remember having those errors, and that has to do with environment setup.
I will look in to it, and let you know, how to properly get it to work.
Here is the file you can take a look on how to create occlusion in Houdini for renderman http://www.cgtalk.ru/forum/attachment.php?attachmentid=6737&d=1148107556 [cgtalk.ru]