XSI Tutorial
How to use Color at Vertices to paint displacement maps
by Dave Lajoie
davelaj@videotron.ca
davelaj@softimage.com


I would like to share a little technique for painting displacement maps in XSI V1.5 The idea is fairly simple. XSI V1.5 has the ability to paint color at vertices. We have a shader node that extract the color and use it to drive material displacement port. And then add subdee to the painted polymesh to refine the surface. Subdee will interpolate Color at vertices automatically. Here is a little script and screen snapshot paintCAV_Displacement_Subdee.jpg Color_Vertex_Displacement_Subdee.vbs How to Paint Color at Vertices in V1.5? Get an polygon object Render->Property>Color at vertices Render->Property>Paint Vertex Color Tool ( or Shift+W ) then paint in the 3d view. If you want to change the paint color you can edit the vertex painting properties by Selecting Render->property->Brush properties. Select the tab "Vertex Color Painting" and change brush color/opacity/bleeding How to connect the shader to extract the vertex colors? The shader is available through various menus 1) Get->texture>Vertex RGBA 2) Get->shader>Displacement>Vertex RGBA 3) Modify->texture->add->Vertex RGBA 4) Rendertree->Nodes->Texture->Vertex RGBA So with this shader you will be able to paint: texture matte, texture blending, displacements, surface colors, etc. Again you are limited to object vertex resolution. How to put increase the subdee level while having color at vertices painted? Select the object Property->Geometry Approximation In Polymesh tab, set Mesh Subdivision level to 1 or 2, or even more if you wish.
Enjoy! Dave.