CGTalk - Doing glow with MTOR/PRMan?

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playmesumch00ns

01-22-2003, 01:54 AM

How can I do a glow with MTOR/PRman? I want to apply it to a certain part of a shader, and also to some particles, like you would with Maya's shader glow.

I remember reading something about image shaders (image plane shaders? pixel shaders?)?

Thanks

rsalonen

01-23-2003, 10:17 AM

What version of PRman are you using? I know that in 11 you can fake glow somehow. I haven't tried it, and I'm no where near it right now.
I saw something in the docs about this, try searching for "glow" or something.
I will check it out when I get home if I find a sollution for it. Can't be too complicated, hopefuly.

Fex

01-23-2003, 11:23 AM

i don't understand why people always want to create
a glow while rendering. For two reasons this makes no
sense:
-first you spend much more time tweaking such
effects in 3d as in a compsoftware (PS, AfterFx..);

-second after rendering animations with such effects
you can't decrease or change it; this is a destructive
workflow

a clever way would be create a output float for your shader
that generates a images that only masks the part and
colors of your scene. Then you could use this images
for a non-destructive composite...

hope this helps :)

playmesumch00ns

01-24-2003, 01:01 AM

Yeah I know, going to do it in post after all... was just looking for a quick solution.

Is there a way I can generate more than one image file per frame with MTOR? Ideally I'd like to be able to render out the mask pass like you mentioned and all the seperate lighting passes in one go. I have a feeling there was a Stupid Renderman Trick about this, but can't remember it now, and I think it was only for raw RIB?

Fex

01-24-2003, 01:23 PM

PrMan could write out multiple images in one go.
Currently i don't have Mtor installed but try to remember it.
In RenderGlobals the "second" tab includes those passes
any shaderparam (like floats,colors,normals..) could be rendered
out secondary.
You have to define this value in your shader as output (newer releases of SLIM provide this to). I think theirs a chapter in
PrMan online docs about passes.

hope you get it working :)

somlor

01-25-2003, 12:59 PM

Check out the public Renderman forums over at Pixar: https://renderman.pixar.com/forum/ ... there is a good thread about doing Glow effects (https://renderman.pixar.com/forum/showthread.php?s=&threadid=487)

(s)

playmesumch00ns

02-03-2003, 08:59 AM

Fex -> cheers, I'll check it out. Think I'll do it this way...aargh time's running out!

somlor -> hehee! that's my thread!

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