This works. I think you missed what DAGJ said about "flip"? Also, you don't need to do PositionEntity every loop, and you only need UpdateWorld() if you're doing collisions or animation.
Graphics3D 800,600 light = CreateLight() camera = CreateCamera() cube = CreateCube() PositionEntity cube,0,0,200 While Not KeyHit(1) ;UpdateWorld RenderWorld Flip Wend