You were talking about lighting. Very interesting!!! You were saying that certain formats of lights needed, plus a physical positioning (3D coordinates), ... a vector (determined by dx, dy, dz) to indicate where it was going the light beam. You were explaining -THX!!!- the existence of X-Plane's axis NORTH, SOUTH, EAST, WEST and its relationship with X, Y, Z... ok I think that It would be necessary that the light vector coordinates were LINKED to OBJ (3D) ... because if the lights point to the N. .. and I do a rotation in the OBJ (in WED) ... lights STILL pointing towards to N. So I think (correct me if I'm wrong) that light coordinates are INDEPENDENT of OBJ 3D design coordinates... so you have to configure the light vectors for each OBJ movement... =========== A test of lighting in my light-pole. In "Blender coordinates" should be XZY...so my light is situated at 38 meters above center of my OBJ reference point LIGHT_PARAM apron_light_billboard 0.00000000 38.00000000 0.00000000 0.150 -0.455 -0.150 0.5 6.0 0.150 -0.455 -0.150 ---> head to SE and going down...about 25º These kind of lights ALWAYS point at the same direction!!!...so in most cases it generates incoherency with de geometry or structure of the OBJ Regards