10 replies to this topic

[hopbin9]

Hi,

I'm working on animating a COP network to be used as a texture and I can render it to a file sequence, but it would be cool if I could just reference the COP inside a VEX shader directly.

I've seen things with Node references in Houdini, where you can go opdef:/Shop/thingy?filename and it can reference something in an asset or OTL.

It would be cool, if you could go something like "chop:/mycomp/null" in the "texture map" field of a SHOP/VEX Decal, then the shader would render using a texture generated by the COP directly. Saving me the trouble having to use an image file.

Is something like this possible?

[malexander]

Yes this does work, as long as it's done in a material or SHOP node, and not in a VOP.

[hopbin9]

Cool, so I have use to properties then to pass it to the VOP level.

What is the syntax for referencing the COP output?

[Macha]

Like this?

Be careful though. I've done that before and had some problems with updating.

[Macha]

forgot file...

Attached Files

•  coptex.hipnc   267.79K   124 downloads

[hopbin9]

thank you! That's awesome. I got it working.

This is going to save me a ton of time

Thanks guys!

[hopbin9]

Macha, on 02 February 2011 - 06:56 PM, said:

Like this?

Be careful though. I've done that before and had some problems with updating.

OMG! I think I now know what you were referring too.

I'm having a very difficult time trying to get the COP reference to update. The COP is loading an image sequence, and then doing some effects on it. I'm then referencing it as a texture for some instanced nodes. My problem is that it's only rendering one frame from the COP!

In the COP is a file node that reads in an image sequence like "image.$F4.png". When I render an image in Houdini it renders the current frame, but when I render on the farm all the render machines render only 1 image from the COP. As each frame is rendered they are all stuck on the same "image.0001.png" file (even if they are rendering different frames).

Nothing I've done has been able to fix this problem. Anyone have some ideas for me?

Thanks,

[Macha]

Uhm....do you refer to it with an expression containing op: ?

If so, try to add [$F] to it, and see if that helps. For example:

op:/img/comp1/OUT[$F]

Edited by Macha, 18 February 2011 - 01:31 AM.

[evgen]

Same problem with COP.
I tryed to set start frame in geometry node to $F but doesnt helps
Maybe we should put somwhere in houdini network script which will render COP/out node every time when network is cooking

[hopbin9]

I tried adding $F as a parameter to the COP nodes, but didn't help.

Thanks for the tip @macha, I'll give that I try.

I ended up giving up on it, and saving out all the textures to images. So it's rendering correctly now. Maybe that's better approach anyway, since I often have to render a scene multiple times to get it right and the COP network isn't modified anyway.

[Benyee]

But how to fetch point color info as animation texture sequence for cop or write out to disk?