Maybe it is something else? Since I tried this:
and it seems to work okay.
Graphics3D 800, 600, 0, 2 SetBuffer BackBuffer() cam = CreateCamera() MoveEntity cam, 0, 0, -15 hatchclosed=CreateCube() hatchopen=CreateCone() EntityAlpha hatchclosed,1 EntityAlpha hatchopen,0 While Not KeyHit(1) If KeyHit(35) Then which_one=which_one+1 Select (which_one Mod 2) Case 0 EntityAlpha hatchclosed,1 EntityAlpha hatchopen,0 Case 1 EntityAlpha hatchopen,1 EntityAlpha hatchclosed,0 End Select EndIf RenderWorld() Flip Wend End
and it seems to work okay.