View Full Version : GI pass? shadow pass? reflection pass?

03-03-2004, 08:10 AM
I like to try to get into some multipass rendering. I rendered out a scene then made a GI pass by making everything white in the scene (nothing else, no spec, reflect etc.), turn on GI and then composited it in photoshop with a multiply mode. Seems to work good.

Is that how it's usually done? How about a specularity, reflection and shadow pass (core and cast shadow)?

Can anyone point me to a tutorial?

Looks like fun (in an anal obsessive way) if I can figure more of it out.

Thanks for any help,

03-03-2004, 11:14 AM
There are a few saver plug-ins in the image process tab that can save out the different channels of a LW render. Try playing with Save Buffer (or buffer export?) and Photoshop Export.

The buffer one lets you save (and name) frame sequences for each of the selected channels. The photoshop one will save PSDs with each channel being a separate layer. You'll have to set the transfer modes and maybe rearrange things, but all the info will be there are separated.

You'll have to render the GI pass separately.

I'm not sure if the names of the things are exactly right because I don't have LW in front of me at the time.

03-03-2004, 12:55 PM
Thanks man.

Watched the tutorial. Yeah, he puts them in this order (with noted mode):

reflection color-screen mode
specular shade-screen mode
raw color-multiply mode
diffuse shade-screen mode

Now I haven't tried it yet, but I need to try and see where my GI pass goes and in what mode.

Any other input?

Thanks again,

03-03-2004, 05:18 PM
Have you looked at this?

CG Talk > Application Specific Forums > Lightwave 3D > Multipass Rendering with Sliders (sample files included) (http://www.cgtalk.com/showthread.php?s=&threadid=93031&highlight=multipass)

03-03-2004, 05:33 PM
Kurtis.....tut, tut


And here's the newtek version

Rob T

03-04-2004, 01:31 AM
Hey Now! Don't give Kurtis a hard time, he visits here too seldom as it is! Be nice to him so maybe he will stick around.

::hands Kurits a beer and pulls up a nice EZ-chair for him.::

Stick around Kurt, we could use you around this forum!

03-04-2004, 07:28 AM

Thanks for the link. I hadn't realized he had posted it to our forum as well.


Thanks for the comments. I have to squeeze the forum in between calls and e-mails, but I try to help where I can.