CGTalk - Two Nuke questions

H3ro

09-12-2006, 04:49 PM

I have a small dark edge around my CG object that I want to comp into live fotage, is there a way to remove it? It probably is, I just dont know how.

I also would like to make the shadows for the object a bit more transparant (shadows are seperate layer) How do I go about doing this?

Thanks

saltchrome

09-21-2006, 06:46 AM

With your cg object, does it have black lines because it was keyed out? Or is this an alpha'd layer doing some strange stuff? I think I probably need to know a little more about the footage.

H3ro

09-22-2006, 12:47 PM

I think it has something to do with the alpha layer, as it is a fully CG object.

Its my first composition project, so I am not really sure of what I am doing.

Thanks

DoubleSupercool

09-25-2006, 04:36 AM

I can't say I have used nuke much (okay, I have only opened up the PLE once!) but it sounds to me like a pre-multiplication issue. Check the nuke help for how to deal with pre-multiplied CG elements.

As for the shadows, try using the shadow element as a mask on something like a brightness node. That is, instead of just laying the shadow over the background and changing its opacity, add a brightness node to your footage and then use the shadow footage to mask where the brightness is. This might give you more control.

T-bat

09-25-2006, 08:35 AM

CG elements are usually premultiplied, so if you have premultiply node between CG and compositing node, delete that premultiply.

CGTalk Moderation

09-25-2006, 08:35 AM

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.