Now I've modified the rotation matrix to scale a cube into a cuboid. Below code works for me.

(I currently use no textures though;

perhaps texture coordinates are affected in some (inappropriate) manner. (?))

Thanks Egon for your quick reply :-)

`box = Primitives.getCube(1f);`

box.rotateY(Util.PI / 4); // cancel jPCT's default rotation around Y

Matrix scaler = new Matrix();

scaler.setDump(new float[]{

halfExtents.x, 0, 0, 0,

0, halfExtents.y, 0, 0,

0, 0, halfExtents.z, 0,

0, 0, 0, 1 });

box.getRotationMatrix().matMul(scaler);

box.rotateMesh();

box.build();

// Reset rotation matrix so above scaling is not applied twice:

box.getRotationMatrix().setIdentity();