Thursday, July 30, 2009


I've tried understanding linear workflow before, but never seemed to get over the hump. I think I'm finally grasping why people use this technique.


It really bothered me that textures never render quite the same as I had painted them. I also use to wonder why using lights with linear decay looked better than lights with a physically accurate inverse^2 (quadratic) decay. Who knew I was just texturing and rendering incorrectly for the past 4 years- and why didn't they tell me? Now that I know, it's hard to sleep. I don't know if it's cause I'm excited or upset- or maybe it's just cause summer's quickly coming to an end :P

ps. coincidentally I used the same wood texture in this test as I used (incorrectly) for my floor in the previous post.


Francesco Giroldini said...

welcome to the club

Francesco Giroldini said...

oh, by the way, how do you change the gamma in renderman? do u simply render in openxr and apply a gamma correction afterwards?

rShow said...

I figured you were in on the workflow, you were actually one of the people I considered asking about this, but I was so confused at the time I wouldn't have known what to ask.

For this render I change the gamma to 2.2 in renderman while I was doing my test renders (Under the passes tab in render globals, the input on the right for exposure). Later I changed the gamma back to 1 when I did my final render to openexr. I didn't need to gamma correct it in post (as far as I know) because I was rendering to the openexr exposure and I had gamma corrected the texture before hand. When I convert the final render to jpeg or whatever the destination output might be, I just convert it and maintain the exposure I rendered the exr at. Does that make sense? Am I approaching it correctly? I worry that might be losing data but I assume if I keep everything 16 or 32 bit I'll be safe.

Next week I was going to see if there's a good way to create all my textures in linear space instead of gamma correcting them.

Francesco Giroldini said...

Yeah, the whole thing makes total sense inside mental ray, 'cause I don't need to gamma correct the textures, but inside renderman, it's just too much of an hassle to gamma correct all the textures... especially if a lot of your set is a matte painting...I'm still in the process of figuring out a good workflow for thesis.
I might end up just rendering in openxr 32 bit and fixing stuff in compositing afterwards..

Amalia said...

Wow. Thats a beautiful ball.... I guess I need to figure out what you're talking about asap. lol

Joon said...

This looks so realistic! How did you make it? :)