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  • Published 7 May 2022

Geometry nodes: Separate Geometry get "coverage" input

(Note: It appears that I misunderstood how the Separate Geometry node functions and that there may be a different way to achieve the process I am after. I am going to try to understand it better and then update this post. But for the time being it seems that perhaps this feature request is not a particularly good one)

Right now the Separate Geometry node allows you to separate geometry based on an input UV map. The issue is that the node will only "include" a face in the separated geometry if (and I am guessing here) more than 50% of that face has white pixels.

What I would like to see is an input that can control where that threshold is. So that if a face is only covered by, for example, 20% white pixels that it still is included in the separated geometry.

For example, assuming the following mesh with a UV map:

mesh_with_map_v001.png

using this node graph:

Simplified_node_graph_v001.png

You get this:

Separated_mesh_v001.png

Whereas I would like this (assuming the min coverage has been set to 0% - meaning if any pixel in the face is white, the face is kept as part of the separated geometry):

Corrected_separated_v001.png

Here is how I envision something like that working:

UI_v001.png

50%

Development Status: Open

Upvote 2 Downvote 2
bvz
7 May 2022

3 Comments

modormoder
  1. You don't know about the average color of the polygon, you know about the color of the texture in the very center of the polygon (with interpolation between pixels)
  2. you are injecting a color into the selection socket when you should be using a compare node
  3. I'm not sure that a comparison node is defined for the color, in this case you need a way to convert the color to a scalar, most likely you need a simple cast through the average, this is supported by a simple color injection into the float socket
4
bvz Author

Thanks for taking the time to explain all of this. I don't fully understand everything you mentioned, but it offers me a lot to start researching. Greatly appreciated!

But the one thing that is made clear is that the coverage is not how it determines whether or not to include a face or not (I was totally mistaken about that).

I will put a note at the top of my post indicating that people should read the comments and that this feature request might be something to skip (at least until I better understand how to use this node).

thinsoldier

You should post this in the GeoNodes thread on BlenderArtists forum. They might know of a way to get it to behave how you want.

1