Is it possible to add a compound shape when using Physijs's addWheel function (in conjunction with Vehicle), as you cannot use wheelparent.geometry which does not include the children's geometry? The geometries of the children use indexed buffer geometries, and I tried using merge to no avail (this question refers).
I guess that's a no, it cannot be done. What I did was create my own function to merge all the vertices, correctly indexed, then uses the new geometry to create a new wheel shape.