Hi!

Is it possible in Houdini to paint in viewport but not ON POINTS, but on textures? this is - paint and save information about paints on the image on the disk, not in points?


This would be very helpfull when painting for example hair attributes, when we would to change these attributes between points - but no as simple interpolation.

Thank you

Not possible to paint in to bit maps in Houdini at this time.

You can RMB (RightMouseButton) on any SOP and save out a uv wireframe to import in to your paint package…

Thank you very much

Are there any news if it would be possible in the future, or I should give rfe on it?

Bump.

Is this on the roadmap at all? I would be very interested in seeing this feature, particularly with ptex support.

I may try my hand at the HDK at some point to see if I can get this functionality, but currently that is a bit beyond me.

I think you're better off at using a dedicated 3D paint package.

PS. Also note the existing prices on such packages as well.

In qLib there's an asset pair called UV PointCloud, where a SOP essentially generates a 3d point for each UV pixel (then you can apply colors to this point cloud with any method), and the COP counterpart which renders these points into a 2d texture.

(And Houdini handles the pcloud SOP->pcloud COP render->3d-view-texture interdependency pretty well.)

The first link below shows a wetmap technique that generates a 2d texture sequence.

(But naturally these are intended to be tools for procedurally generating UV-based textures, not for artistic-painterly purposes.)

https://www.facebook.com/video.php?v=872881069412345 [facebook.com]

https://www.facebook.com/qLibHoudini/photos/a.396009720432818.98425.145692112131248/872867132747072/?type=1 [facebook.com]

ps.: Actually, having another tool to convert the colored pointcloud into a ptex wouldn't be a bad idea (e.g. to use it as a base in a 3d paint app), but I'd be surprised if Houdini could write a ptex file.

It may be (just barely) possible to make an asset to do this in Houdini without resorting to the HDK, though I'd guess it would probably be quite complicated. You can use the Draw Curve SOP to draw curves on a surface. You can get the texture-space uv coordinate of each point in each curve by putting the surface primitive number (stroke_prim) and primitive uv coordinate (stroke_uv) into Attribute Interpolate and telling it to interpolate uv, (you may need to do an Attribute Promote of stroke_prim and stroke_uv if uv is a vertex attribute, and set Attribute Interpolate to interpolate vertices). Figuring out where in the texture the brush overlaps is a bit more complicated, but it's most likely doable with a bit of math and a bit of VEX.

As for making it fast, that's another matter. :wink: