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rendering points with per vetex color?


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I've got a ply file with the point cloud , points have color information.

Now , is there a way to render them retaining color?

It's a research project, some 3d aquisition technique, and this point cloud is rather dense -about 2 mil points.

Any advice appreciated

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Ah, yes. You will find that many of the default shader SHOPs do not have support for point color attributes but there is one. Use the SuperMaterail SHOP. It does look for point color "cd" attributes and if they are bound, it will add them to the supplied diffuse color.

Another thing, if you are just rendering points and a lot of them, you can render them as points. Go to the object parms and in the Render folder, set the parameter called Geometry to the option "Render only Points". I have pushed this past one million on many occasions but please keep the attributes under control as you will run out of memory and only on systems with 800MB or more of physical memory.

The other approach is to build a shader from scratch using VOPs. In that network, put down a parameter VOP that is called "Cd" (always omit the quotes for strings) to pick up the "Cd" attribute in SOPs (have to match exactly for this to work, just RMB on the SOP with Cd attributes to get the correct syntax) and check on "Use Input Value If Parameter Not Bound". Multply this by a color parameter or Lighting Model...

Note that you know that you can pick up Cd, you can pick up any point attribte bound to the geometry using the above technique. Geo paint on some blending channel attributes. Sky is the limit here.

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A quick and dirty way of using the default shaders with point colors is to use the Attribute SOP and rename the "Cd" attribute to "diff". Which is what most of the shaders use for their diffuse surface color. Its quick and it saves you the time of going in and creating VOP networks. But in the long run you will usually end up making a VOP network anyway. :P

jim.

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