Hello,

I am trying to do the “working with sprites” sidefx tutorial with renderman as the renderer. I am kind of stuck after I have created the particle emitting object since I don't know how to tell renderman I want to assign sprites to the particles…
Any help would be appreciated, thanks.

any clue anyone? :?
I am really stuck. At least if someone could give me a few hints. It'd help.
thanks

I'm not familiar with that particular tutorial, nor am I excessively familiar with renderman, so perhaps there are easier ways than the following:

1. Houdini ships with a procedural which can render particles as sprites. I'm assuming that it is possible to write (or find) a renderman procedural that will do this for you as well.

2. Using the copy sop, and the particle system as the template input, you can copy a textured grid to each particle position. You can use either a lookat POP in the particle system, or a primitive SOP after the copy SOP to orient the grids to face the camera.

3. Similar to #2, but you may be able to get away with using point instancing at the object level. See the render page in the parameters for a geometry object (the “Point Instancing” and “Point Geometry” parameters in particular).

It is quite possible that renderman does not support a sprite render as implemented in Houdini. But I'm not up to date on Prman myself, so it is only a guess.

thanks a lot for the hints, I'll give it a try…

actually, the copy method works but i guess instancing should be less ressource consumming… But it seems that there's no rman sprite procedures like the one you can find for mantra.
You mentioned writing the procedure myself. How should I start, knowing that I have a C programming background? Any docs,tuts … links?

thanks a lot

I only mentioned procedurals because I understand that renderman supports them, but that's about the extent of my knowledge in that area for renderman. Maybe somebody else will be able to provide more useful information.