Houdini 16.5 Nodes VOP nodes

Front Face VOP node

Returns the front facing normal of a surface, given a surface normal (N) and an incident ray (I).

This operator returns the front facing normal of a surface, given a surface normal (N) and an incident ray (I).

If I or N are not wired, the global variables by the same names will be used instead. Neither vector needs to be normalized. There is an option, however, for the output to be normalized.

The dot product is negative when N and I head in the same direction. So for semi-transparent materials, you can make the back face shade correctly by flipping N: if(dot(N,I)>0,-N,N).

Note

When baking a map, it still uses a dicing camera point. If you have a camera on one side of an object, the reverse side has trouble if you frontface().

See also

VOP nodes