Itoo Software Forum

Author Topic: Distribution by Vertex Colors  (Read 1479 times)

Shawn Olson

  • Jr. Member
  • **
  • Posts: 75
  • Wall Worm
    • Wall Worm
Distribution by Vertex Colors
« on: October 25, 2013, 02:59:07 AM »
I would like to have the option to use the vertex color, vertex alpha and vertex illumination channels available for controlling distribution.

Also, I would love to have a new parameter that works in conjunction with the Probability spinner for each geometry entry in the geometry rollout: a vertex color/alpha bias. This would increase the odds of that object appearing at any point where the alpha matches the bias.

To explain, imagine you have a terrain that is a valley with a river running through the middle. The terrain has a material that blends between Hillside and Riverside using the Vertex Alpha channel. Now it would be convenient to be able to say that pine trees have a bias for alpha 0.0 (hill top) and smooth stones a bias at 1.0 (river ). Since the bias just increases the odds, most rocks appear at bottom but a few up top, and vice-versa for the trees.

I would like to see Vertex Alpha support because of a tool I am building for a game engine pipeline where foliage is distributed by vertex alphas in a similar fashion explained here, and I'd like to be able to use Forest as an available avenue in the whole process.

iToo

  • Administrator
  • Hero Member
  • *****
  • Posts: 3319
    • iToo Software
Re: Distribution by Vertex Colors
« Reply #1 on: October 25, 2013, 10:02:45 AM »
Although a bit tricky, currently it's possible to use Vertex Color for the Distribution Map. In the following way:

1) Select Vertex Paint->Map Channel in the VC modifier.
2) Use the same map channel in Distribution->Map Channel, and enable Surface->Auto if you want to paint interactively.
3) Set Distribution->Diversity to Match Color ID on Map

From here, you can assign a color for each item in the Geometry List (Color ID), witch matches with the vertex color. To paint empty areas, use black color. If you want to add some level of noise, use the Noise parameter of "Match Color...", or combine the VC map with a procedural Noise texture.
Carlos Quintero
iToo Software

Shawn Olson

  • Jr. Member
  • **
  • Posts: 75
  • Wall Worm
    • Wall Worm
Re: Distribution by Vertex Colors
« Reply #2 on: October 27, 2013, 06:11:07 AM »
Thank you for the input. I tried a basic setup similar to this but failed... I will try again tomorrow. Perhaps it was because the map channel I tested was -2 (vertex alpha) and it was out-of-range? I say this, since I know that the Vertex Color map itself doesn't let you set it to vertex illumination (-1) or vertex alpha (-2). For my specific needs, it has to be -2 since that is something all the tools I'm working with use.

In any event, I will do more testing.

Again, thanks!