help-various renderman shaders on the same object

#1

Hi!

English is not my native language, so please, excuse me for
grammatical errors and poor phrases.

I’m trying some experiments with renderman engines modifying the famous
Pharr skin shader:

http://www.dedalo-3d.com/index.php?filename=SXCOL/docs/archive/05-05-15_ss_scattering_renderman.html

As you seen in the last image in the page above, when I use the shader,
it, of course, is applyed on all mesh, so the model has skin eyelashes,
skin eyes, skin teeth, skin nails, skin tongue etc…
A way to fix this is export the mesh as differents pieces, and assign a
different shader to each piece. But I think this is a brutal way…
Besides, splitting the mesh in two parts, and rendering as subsurface, should return some problems in cut zones, that will be rounded…

Do you know some tricks?

thanks, Manuel

#2

EDIT:
On second reading, I may have interpreted the post incorrectly (hey, it’s 6 AM, give me a break :banghead: ). Renderman ships with a ‘Mix’ material that can be very useful for applying different materials to certain parts of a single mesh. You’d paint a quick b&w mix map (all white where one shader should be used, all black where the other should be used) and apply your two shaders as the colors to use in the mix material. Works well enough.
I imagine that it’d be pretty easy to do a version of the mix material that accepts more than 2 colors (maybe one shader is applied where the mix map is all red, another where it’s all green, etc.), but I’m now aware of any that have already been written (you can, of course, also use a mix shader within a mix shader to break your model down into more sections). Unless what you’re trying to do with your textures starts getting really complicated, a mix shader should do the job.

#3

Thanks!

Another method is write a code like:

WorldBegin
AttributeBegin
Surface “body”
PointsPolygons […] […]
“P” […]
Surface “head”
PointsPolygons […] […]
“P” […]
AttributeEnd
WorldEnd

However I must try what happen rendering it with subsurface…

#4

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.