[Sidefx-houdini-list] Point Attributes to Instanced Geometry
mark at sidefx.com
Thu Oct 26 13:29:38 EDT 2006
On Thursday Oct 26 at 12:08, Robert Persons wrote:
> I'm using point instancing and would like to transfer attributes to the
> instances. In this case I'm instancing a 3D house model to points on a
> 2D poly. Each house has several materials. I'd like to transfer the
> Alpha and Cd attributes from the points to all the points on the
> instanced model. I could use the copy SOP but we're talking of hundreds
> of instances so the geometry would get too dense . I really need to use
> point instancing in some way.
> Any Ideas?
The easiest idea would be to stamp a shader on each instance.
It's not possible to modify the geometry of the instance, but it is
possible to change the surface shader.
Here's a simple .hip file which shows what I mean.
The important things to look at are:
- The expressions for the diffuse color in the plastic SHOP (in
the points object)
- The shader SOP is creating hard strings on each point rather
than indirect references to the SHOP (so that stamping works)
- The shader SOP creates point shaders (rather than binding to the
If your house model has multiple shaders, this gets a little trickier,
but it's do-able, just a little more work and clever thinking
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