View Full Version : compositing for stills: noob question

04 April 2009, 01:32 AM
I'm looking for some advice on how to better composite 3d renders or any outside image into a piece of art i may be doing using photoshop. For 3d renders is it better to render out a png or targa file and run a defringe filter a few times on it or is it better to render out a jpeg and use the various selection techniques within photoshop to extract the image? I'm kind of in a weird spot because everything I try doing seems to hinder my work flow and hurts the quality of my work.

Thanks everybody :beer:

04 April 2009, 12:17 AM
I am not too sure where you are going with this. I don't know why you would be needing to defringe your 3D renders. As for format, stick with some lossless or close to it that can have an alpha channel, such as .tga or .tif

Never render JPEG's for compositing. Ever. Maybe for playblasts, but never for final shots.

You might need to post a screenshot to give us a better idea of the issues you are facing.



04 April 2009, 04:54 AM
thanks for the feedback! i previously used jpegs with a render matte of the object i wanted to composite into a picture. I guess I wont be doing that anymore.

Sorry if the question was a bit vague, but it was just a hypothetical scenario. I just wanted to know what you guys had to say, because I felt the way I was doing it was ruining the quality of my work.

Thanks again!

04 April 2009, 12:52 AM
Yarrr, a JPEG image with a separate render matte will never "cut out" properly because the compression will most likely be slightly different on each file.

Just render out a TGA at 32bits (24bits colour, 8bit alpha channel) and you should be fine.

04 April 2009, 12:55 AM a defringe filter a few times...

if your getting fringe around your alpha channel's edges maybe your saving with a straight alpha channel (not pre-multiplied)? try saving the 32 bit .tga with pre-multiplied alpha

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04 April 2009, 12:55 AM
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