did anyone successfully import the cop's ramp into Vex builder (for building rman shader)?
I went through the tutorial below but could not get it worked.

http://odforce.net/wiki/index.php/FrequentlyAskedQuestions [odforce.net]

I input “opimg/img1/ramp1” for the texture path,
but the node turned yellow and said “cannot have channels which depend on time”

Can anyone show me how to import a Cop's ramp into Vex builder for building a rman shading network?

That's actually a tip for accessing them into shaders built from VEX not for importing them directly into the builder.

That's actually a tip for accessing them into shaders built from VEX not for importing them directly into the builder.

Could you pls show me this tip? Because I may want to build a shader with circular ramps. In mtor, the ramp from slim is already quite good.

Well it just means if you make a Vex shader and one of the parameters is for inputing the location of a texture map you don't need to point it at a file on disk you can point it directly at a cop in a cop network. The cop that you point it at doesn't have to be a bitmap it can be a ramp cop. That's all there is to it, it's not something you code for it's just Houdini functionality. Just happens to be a rather hidden bit of functionality.

I still got “cannot have channel which depend on time ” on the node while making a texture parameter link to the COP's ramp!
Can someone show me how to link a ramp (e.g. cop's ramp) to Vex builder?

brucelay
I still got “cannot have channel which depend on time ” on the node while making a texture parameter link to the COP's ramp!
Can someone show me how to link a ramp (e.g. cop's ramp) to Vex builder?

Notice that Simon said shader, not “Vex Builder”. A subtle distinction but it makes all the difference in this case.
You can't have time-dependent values for VOP parameters, but you can put any expression you like in a shader parameter.

But here comes the part that I don't think you're going to like…

IMPORTANT: This technique will, AFAIK, only work with Mantra; not PRMan (!!)

For PRMan you'd have to first save the ramp as a .tx file and use *that* as a texture.