Hello

I am trying to make a procedural advertising billboard (see image). I am quite new to UVs in Houdini…

I have tried two ways: copy to points and MOPs but the key issue is how to apply the uvs correctly.

Ideally it would be possible to have three different textures for each side of the prism

MOPs is great for creating the flipping animation but I cannot add UVs in the middle of the MOPs workflow…

There are notes inside the file.

Seems like a useful set of capabilities….

Any help is much appreciated

SOLVED!!

A kind stranger at the MOPs forum replied to me (thanks @toadstorm!) with a solution

I adapted his file to work with Redshift as well

I post it here for anyone interested


Here is what he wrote:
“The most straightforward solution is to unpack the instanced geo, project UVs, and then re-pack as packed fragments before handling the transformations (MOPs Convert should be able to handle this). There might be a trickier way to handle this by using a custom Mantra shader, but I'm not sure it's worth the time to figure out when the unpack > project > repack as fragments workflow is fairly quick to calculate with such simple geometry.

I'm attaching an example file here. There's a couple of gotchas… first, the material assignments are happening BEFORE the geometry is ever instanced, since it's a per-face material assignment, and because of this you need to make sure that the Mantra ROP is set to ”Save All Materials" under Rendering > Render. This is because materials that live inside a packed object aren't by default added to the IFD if nothing else in the scene references them. (The alternative would be to use stylesheets.) Second, each material needs to know what uv set to use for the diffuse texture, so the textures are manually connected to the diff_clr inputs of the Classic Shaders rather than using the built-in texture inputs. You could likely find a clever way to combine all of this into a single material using a Switch VOP and some point/prim attributes, but this works for the example anyways.