CGTalk - material to polygon cluster problem

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Theropoda

03-29-2006, 09:55 PM

hi folks,

i simply want to apply a material to a selection of polygons of my object. that object already has a phong shader, so what do i do? i just select the polygons where i want the other materials, apply a new material with different color and everything looks fine, at least in the editor.

when it comes to rendering, the material which was applied to the cluster doesn't show up. instead, the material which already was on my object renders; if i delete this material, the rendering is just black at the area of the cluster.

i think i've done this a hundred times before, but in this case it just doesn't work and i can't find out what's going wrong.
can anybody help me?

thanks in advance
günter

ElysiumGX

03-29-2006, 11:31 PM

i just created a cube in my scene, and gave it a grey Phong material. Then I selected a face, and assigned a blue Lambert material, which creates it's own cluster. It renders fine.

Could you try replicating that and see how your results appear?

alona

03-30-2006, 12:03 AM

Are you rendering in passes, perhaps? Clusters don't play well with passes. Bernard Lebel has an article on XSI-blog (http://www.xsi-blog.com/?p=75) that explains why cluster materials are the root of all evil, and offering various methods for avoiding them altogether.

AA

Atyss

03-30-2006, 12:27 AM

Thanks for the plug :buttrock:

If it really has to be cluster materials, then I suggest you assign materials only to clusters, and none to the object. That is, the "other polygons" should be turned into a cluster and receive that Phong you have previously applied onto the object.

Oh and before someone smarter than me or doesn't like me jumps in to rip me apart, keep in mind this is my personal opinion, by on my personal experience and from what I have read on forums. You should experiment on your own with these concepts.

Cheers
Bernard

Theropoda

03-30-2006, 09:33 AM

hi,

@ elysium: i can't replicate the problem. it only appears with this specific model. as i said, i've done it a hundred times before and it always worked...

@ alona: i'm not using passes, but thank you for the link.

@ atyss: i'll check out your article and try the alternatives. i've already tried creating two clusters and then applying the materials, but then the second cluster just renders black.
but thanks for writing the article! :)

günter

dwigfor

03-30-2006, 11:08 PM

Do you have a texture applied to the material? It could be that you need to load it into the Texture Editor, and then set it to wrap U and Wrap V..

That's fixed my "Black" renders.....

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