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I have a terrain in Blender (see red inset) and in the material node setup for that terrain I have separated an area with certain geometry features (height, orientation). Its the white area in the picture. (Nodes used : Geometry, Mapping, Colorramp)

My question is if there is a way to select the vertices in the mesh that correspond only to the white area, in order to create a Vertex Group. Now, if I create a vertex group directly from that material it obviously includes de vertices of the black area as well.

Thanks in advance ! Lynxx

Selected area

UPDATE

Thanks Serge and Ray for your comments. I think I am closer to the solution but I cant seem to find the last step.

I have baked the texture and used it as a mask in the Vertex Weight Mix modifier, but I still not clear on how to select only the vertices with a weight of 1 (red ones on the left in the image bellow).

Weight Paint

When I go into edit mode, to assign vertices, all are selected not only the ones corresponding to the red area. I have even applied a Mask Modifier as show below, to mask the blue area, but again when I go into edit mode the whole mesh appears not only the red part. So I cant select only the red vertices.

Masked mesh

Just to clarify, I want to select only the vertices (red part of Weight Paint), to assign them to a new Vertex group, so I can then assign a material to only that part of the mesh.

Thanks again.

Lynxx
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  • Use Vertex Weight modifier, it is assigning weight based on input image parameters – Serge L Nov 02 '17 at 19:54
  • Related: https://blender.stackexchange.com/questions/3355/vertex-group-from-texture – Ray Mairlot Nov 02 '17 at 20:04
  • Thanks @SergeL for your help, I have updated the question to see if I can find the last step to the solution. – Lynxx Nov 05 '17 at 19:14
  • Thanks @RayMairlot, I have added an update to the question to see if I can finally solve it. – Lynxx Nov 05 '17 at 19:15
  • It is not necessary to apply Mask modifier. You can enable all displaying options of Mask and Vertex Weight modifiers (those icons near camera pictogram). Next, you enter edit mode and select everything. It is mandatory to select NOT by clicking A, use selection tools instead (like border (B) or circle (C)). Once you select everything, assign selection to new vertex group. – Serge L Nov 05 '17 at 20:15
  • Hello again @SergeL, thanks for the answer. Sorry to bother you again. I have removed the Mask modifier as you said, but I really can not find where I can enable those options of Mask and Vertex Weight modifiers that you mentioned. Where exactly are those options ? Do you mean the buttons on the right of the modifier panel with these titles ?
    • Display Modifier in edit Mode
    • Adjust edit Cage to Modifier result
     – Lynxx Nov 06 '17 at 00:05
  • Yeah, these two options should be turned on. – Serge L Nov 06 '17 at 07:16

1 Answers1

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Assigning weight

Add Vertex Weight modifier, create empty vertex group, enable group add and tweak few sliders to get it work.

enter image description here

Selecting vertices

Add Mask modifier and select same group as in Vertex Weight modifier. Also enable all display options to see modifiers working in edit mode (inside green box on screenshot)

enter image description here

Next, you enter edit mode and select everything. Press A twice to toggle selection. It is mandatory to select all NOT by pressing A, use selection tools instead (like border B or circle C) with wireframe view enabled Z to speed up things a bit. Once you have select everything, assign it to new vertex group.

enter image description here

To check if you done it right, disable viewport visibility of modifiers. enter image description here

Serge L
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