-
expression to cull back-facing 3d layers
Im sure this is fairly simple, but my knowledge of expressions is very limited. I have a 3d layer that orbits around a 2D globe and need it to be hidden when it appears “behind” the globe (technically it isnt behind, as the globe has no z-depth). i cant make the globe layer 3d, so is there an expression i can add to hide (either through opacity or visiblity) the orbiting layer when it is turned away from the camera? i believe the equivelant in 3D packages is called “cull back-facing planes”.
-
3 Replies
-
This is some code from Dan Ebberts that should do the trick:
a = toWorldVec([0,0,1]);
b = thisComp.layer(“Camera 1”).position – toWorld(anchor_point);
c = dot(a,b)/length(b);
if (c > 0) 0 else 100Apply it to the opacity parameter.
Mylenium
[Pour Myl
-
thanks mylenium – works like a charm.
and thanks to dan as well – discovering his motionscript site has just opened up a world of learning to me! -
Hey guys, for future reference, this one does the same thing more efficiently:
if (toCompVec([0, 0, 1])[2] > 0 ) value else 0
Dan
Reply to this Discussion! Login or Sign Up