[Sidefx-houdini-list] random UV transform

Rangi Sutton rangi at kanuka.com.au
Mon Jul 25 19:28:30 EDT 2011

On 26 July 2011 08:34, Larry Giunta <larry at gcreativestudios.com> wrote:
> Hello all,
> I have a grid that is made up of various sized rectangles ( just dissolved a
> handful of edges to make that).
> I then made the points unique so the grid could deconstruct and the
> rectangles could fly off in different direction.
> I also need a texture map to run across the grid so it appears as a solid
> image when the grid is together.
> Easy enough with a UV texture and appropriate material applied.
> However, I need to randomize the scale of the UV's sightly from primitive to
> primitive so the textured image
> appears to be magnified somewhat differently from rectangle to rectangle.
> I have been trying to use some random expressions in the UV transform's
> scale parameters multiplied by $PR,
> but I seem to be getting a uniform transform across the entire grid ... not
> slight variations from primitive to primitive
> as I expected.
> Am I just looking at the wrong SOP??? or maybe I should be think about a
> different approach to writing this random expression??
> Any other thoughts on how I might slightly randomize the UV scale from
> primitive to primitive across a grid with unique points??

Simply way might be to ...

* Copy the UVs to Position with a point sop (vops for flavour)
* Use primitive sop to scale your prims.. or any sop that floats your boat
* Copy positions back to UVs of your original geo.

Usually there's steps in there for making points unique and fusing
them again and stuff... but you've got unique points already so it's
all easies.


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