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While we are at region rendering

Posted: Thu Apr 19, 2007 8:04 pm
by Stur
Ono, on another topic you post your thoughts about the possibility to render a scene region by region.

If you plan to think on this feature, I have an idea I'd like to discuss here with other people.

By doing test renders here and there, I noticed that glass and SSS materials are longer to converge. Sometime, I've the feeling that my picture is globally nice but some objects are still too noisy. So, if region rendering is technically possible, why not adding an option to choose a region which would not be a simple square, but the shape of an object ?

e.g. I have a scene with a table, some fruits, and a glass. After a couple of hours, the picture looks good except from the glass. It would be great to stop the render, and then to resume it and constrain the rendering region to the glass.

indigo.exe could be launched with an argument to set a mesh, or instance (or both) to render.

What do you think about that guys ? Do you think it would be usefull ?

Re: While we are at region rendering

Posted: Thu Apr 19, 2007 8:36 pm
by Zom-B
Stur wrote:What do you think about that guys ? Do you think it would be usefull ?
extremly usefull if you use cauchy_b :wink:

but much better than this would be a noise detection algo in indigo,
that finds noise and targets this areas, so rendertime doesn't get wasted by shooting on clean regions...

Posted: Thu Apr 19, 2007 9:17 pm
by mrCarnivore
That could lead to problems, since the render gets brighter the longer you render, the region you render more on will get even more bright than the rest and therefore inconsistent...

But I like the original idea of constricting the render to an area to make it cleaner only there.

Posted: Thu Apr 19, 2007 9:44 pm
by Stur
Yep.
But telling Indigo to constrict the render to an area could aslo make it save a mask of the area in a separate png, and this mask could be used for postpro.

Posted: Fri Apr 20, 2007 1:43 am
by zsouthboy
[REQ]Region rendering with alpha masking.
255,255,255 areas get high priority.
0,0,0 get low priority.

Posted: Fri Apr 20, 2007 2:42 am
by Kram1032
what's with reflection?
I think, a detector will make it biased... but the idea is good too.
If there also is a brightness-detector, the brightnessproblem would stop.

That may be hybrid....
(Onoooooo?)

Posted: Fri Apr 20, 2007 5:51 am
by zsouthboy
The brightness thing is not a problem - I think we invented it. At least, my best guess would be that it's not a problem.

Keeping it unbiased, and keeping BiDir working.. that might be though.

Posted: Fri Apr 20, 2007 12:43 pm
by IanC
I would assume there is already an importance sampling algorithm in indigo, I think Ono has mentioned it before.

Posted: Fri Apr 20, 2007 11:16 pm
by Deus
MLT is "importance" sampling built in. Thats the entire thing with the MLT algorithm but you got a point IanC: This is not something that shall be solved with region rendering. It shall be solved in the render itself.

/ S

Posted: Sat Apr 21, 2007 2:53 am
by Stur
Well, fact is that sss and transparent materials are reaaaally slower than other materials to get noise free.

So the aim was to be able to say to Indigo : "Hey man, the picture is almost cool, but please focus your power for a couple of hours on the candles only, now."

Ono said it may not be too hard to implement a region rendering system. So, I was just giving my two cents, regions could be something else than squares. Furthemore, delimiting the region to the shape of an object would reduce visible lines between two regions with different amount of noise.