How to group vertices in Blender for Three.js?

3
votes

What is the best way to group a bunch of vertices in Blender? After exporting I want to manipulate only this group of vertices in ThreeJS (eg. change their position).

I tried:

  • Use the integrated .obj exporter from Blender(v2.73) and the .json exporter from ThreeJS (Add-on "io_three") but they ignored for example Blenders "Vertex Group" and did not separate vertices in groups.

  • With the .obj exporter I somehow managed to have a node (type "Object3D") with 3 children (type "Mesh") instead of 2 children. And in the last child there were some separated vertices of the mesh (but not the ones I selected as a Vertex Group in Blender). This probably would be a good solution if I knew how the vertices got in the other child node.

1
three.jsblender

1 Answers

1
votes

  • Wavefront (.obj) has no concept of grouping or nesting object. Although there is some kind of grouping mechanism where you can group faces with different materials with the annotation g (http://www.fileformat.info/format/wavefrontobj/egff.htm#WAVEOBJ-DMYID.3.1). This behaviour also exists in some kind of way in Blender with the Vertex-Groups. But the default Wavefront exporter in Blender doesn't support that kind of grouping.

  • Once the usemtl attribute (I don't know which Blender setting caused this to occur in my example) is set anywhere in the faces definition of a .obj ThreeJs will separate the faces after that attribute into a new child node.

My solution: Put all objects in Blender (which should belong to one group) into one single object. The exporter then creates an object o for each Blender object. ThreeJS will create a child node for each of this objects. Only problem: Manipulating the original objects in Blender (that are now combined in one object) is more difficult.