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.
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.