MY background draw is set to 3/4 & I do not have fog enabled. The model I am trying to 'vue' is a simple mesh approx. 8km long and about 50m wide - it is a dxf of a road in a mountainous terrain, from a Digital Terrain Modeling package, exported out of AutoCad. I've also converted the DXF to a 3DS file, but get the same result.