I see. Maybe i should give a little more information about the potential problem that jPCT may have with rotation matrices that include non-uniform scaling. It's only a problem if you assign such a matrix to an Object3D as rotation matrix. If you never do this and use it in combination with Matrix and SimpleVector, it's all fine. If you assign it, it will basically work in the way it's supposed to work, i.e. you'll get a non-uniformly scaled Object3D. What won't work, are two things: You can't use scale() or setScale() any longer, because you'll get strange results. That may not matter, because you are obviously doing the scaling on your own anyway. The second and more important thing is, that the lighting intensities will become wrong. When calculating the lighting, jPCT has to apply a correction factor based on the scaling. If it doesn't know the scaling, the correction just isn't correct and your objects will appear either too dark or too bright. This applies to the software and the default hardware renderer. It will most likely not apply to compiled objects, but i've never tested this.