Houdini 12 Shading

The following table shows the equivalent mapping values for VEX and RSL.

VEX RSL
dPds dPdu*du
dPds/Du(s) dPdu
Du(P) dPdu*du or Du(P)*du
Du(P)/Du(s) dPdu or Du(P)
Du(s) du
dPdt dPdv*dv
dPdt/Dv(t) dPdv
Dv(P) dPdv*dv or Dv(P)*dv
Dv(P)/Dv(t) dPdv or Dv(P)
Dv(t) dv
n/a Deriv(a,b)

Differences

Keyword differences

RSL output = VEX export

Operator differences

RSL L.N := VEX dot(L, N)

Syntactic differences

RSL color(1,1,1) := VEX {1,1,1}

Different functions

RSL faceforward() := VEX frontface()

RSL lightsource() := VEX limport()

Behavioral differences

RSL Du(P) := VEX Du(P)/Du(u)