Extrude by colour

[reeson]

Hey guys. I'm trying to get extrude by colour to work, but I'm failing hard. What I have is a grid that I painted some spots over with red colour. Now, how can I extrude only red colour, with a falloff? I did find some old videos for Houdini 15, and I tried to recreate, and it doesn't work. Cheers!

exturde by color.hip

[konstantin magnus]

1. It is better to paint on a black surface right away, because that way all color channels are initially set to 0.
2. After painting you should promote colors to primitives, because this is what primitive extrude is working with.
3. If however you have chosen to paint red on white, the red channel will be set to 1 everywhere. Red = 1,0,0 and White = 1, 1, 1.
4. Thats why the green or blue channel is more distinctive here: Set your primitive wrangle to f@r = 1.0 - @Cd.g; so its able to tell where red is being used.
5. Inside the primitive extrude set 'distance' to something larger than 0 and set 'distance scale' to r.

 

exturde by color_corr.hiplc

[reeson]

Thank you. I see now. It's easier with a black base colour. So once I paint over with red, in primitive wrangle I just type f@r = @Cd.r 

Cheers!

 

[reeson]

Is there a way to add an additional noise on top of the extrude by colour without adding another PolyExtrude SOP? I'm trying to do this with Att. VOP, but no luck. Here's my hip file.

color_extrude1.hip

[Sepu]

You need to bring your attrb into Vops here is a fix version, if you need a reverse add a fit range.

 

color_extrude0_fix.hipnc

[reeson]

Thank you!