public void MakeSimpleSetup(uint gfxObjID)
{
_setup = SetupModel.CreateSimpleSetup();
Parts = new List <GfxObj>(1);
var gfxObj = GfxObjCache.Get(gfxObjID);
Parts.Add(gfxObj);
// always identity?
PlacementFrames = new List <Matrix>(1);
PlacementFrames.Add(Matrix.Identity);
}