simport(): no signature/can't assign void

[cgdougm]

Anyone else come across problems with simport()? I was some discussions about fog but didn't seem related.

I'm trying to get the surface variables "Cd" and "Alpha" as used in the point SOP.

If I try to use the "Import Surface Variable" VOP I get an error saying:

Cannot find a signature with the correct arguments and return type for the "simport" function.

A value of type of "void" cannot be assigned.

// Code produced by: simport1
found = simport("Cd", val);
if( found == 0 ) val = {0.0, 0.0, 0.0};

TIA

Using Houdini 11.0.733, win7

[symek]

Cannot find a signature with the correct arguments and return type for the "simport" function.

A value of type of "void" cannot be assigned.

Sounds like you're doing it in SOPS or surface shader, aren't you?

If so, Import Surface Variable VOP (and underlying simport()) is meant to be used inside light/shadow/fog shaders. In surface shaders or in VOPSOP you use geometry attributes by creating a parameter/variable of the same name and type. So a parameter called "Cd" of type "vector" will be overwritten by geometry color attribute.

Edited September 30, 2011 by SYmek