Multipass rendering?

[m-koperwas]

Hello !

A newbie question : How to render in multipass with PrMan ?
I want to extract image beauty, shadow, specular, etc...
I didn't find any options on RAT interface, it is a combiner script ?
a custom RenderMan controls ? please help me, because I always work
like that with Maya Software Renderer or Mental Ray.

Thanks

PS: Sorry for my bad english

[aubec]

PRMan and RAT have no "built in" method of multipass rendering. You could look at the "context" functionality as a way of building shaders that are compliant with rendering passes, or you could render arbitrary outputs to do a similar thing. In order to do that you'll have to familarise yourself with RenderMan Shading Language.

PRMan does not do much "out of the box", you have to make this kind of thing for yourself, I'm afraid. But on the plus side, this makes PRMan much more customisable, and configurable to your own specifications.

Hope that helps

A

[m-koperwas]

Thanks Andrew W, with your reply, I've win a lot of time and I'll work to this long and hard way... For the moment, I learn with ZJ & Nrender tutorials about shadow pass and rib box.

gromfx

[m-koperwas]

About arbitrary output variables, I found a very cool slim template to do that. The author is Mesh, a russian cg artist, and is .slim works properly.

http://www.renderman.ru/files/index.php?PH...;directory=mesh

[darth-1]

You can find a little bit updated version of this template and short explanation of "how to use it" here:
http://www.alfacom.net/~mesh/files/multiOutput/

[subjectego]

this is wicked Mesh, thanx a bunch! Can't wait to get to work and try this

[subjectego]

can't seem to get my shadowpass aov rolling. I'm rat5.5.1 (__inShadowC). I've tried with all the other geometry connected to the node and without any, do you have to have all geometry related shaders connected to the node? Is ensemble a must(?)

[darth-1]

can't seem to get my shadowpass aov rolling. I'm rat5.5.1

Use __inShadowC for lights with attached Slim Light Appearances only.
If you have maya lights with default mtor light shaders (mtorSpotLight, mtor... ), then use __inShadow.
And certanly, you have to connect this multiOutput template to all geometry that should be in __shadow pass.

[subjectego]

excellent, does work bugged out on my first scene for some reason (probabbly I forgot something). The only "problem" I see so far is that it writes shadows to diffuse channel as well making it harder to multiply/add etc. shadows with a value less than black (or no?) but it would be cool if a diffuse pass would be generated "without" shadows, is that possible? Also, is there a way to tell renderman to mix these for the regular display output image (not the secondary)? As it is now it renders whichever parameter is sellected in shader editor in slim (ie. __color or __difuse only). But the shader really rocks!

[rudycortes]

I have put together a small tutorial on how to do Multipass Rendering with a RenderMan renderer.

http://rudycortes.com/tutorials/

I have also included all the source files. There is a link at the bottom of the tutorial. or you can get them here

http://rudycortes.com/tutorials/rmantuts/multipass.zip

Its not hard at all and im sure those gurus among us will not find it interesting, but this tutorial is "for the rest of us", you knew it had to happen sooner or latter.. RenderMan for Dummies!!!.

This tutorial assumes you have basic knowledge of the working of your RenderMan renderer. I will write more basic tutorials for those who have never rendered anything with RenderMan. I'll keep adding tutorials as I write them. Any feedback is greatly appreciated.

Just a warning.. The website is very simple. I'll do something nicer when I have more time.

CHEERS!!!
Rcortes

[m-koperwas]

Hello to everyone !

I'm a newbie on RenderMan, I started since 6 mouths ago with Essential
RenderMan Fast,
Advanced RenderMan and RenderMan Interface Specification 3.3 (RAT doc).
I 'm working with RAT 5.5.1 on Maya 5.0 for my first showreel and a
personnal project.
I hope to render all with PrMan, but now I see the complexity of this task

I know how to split a .sl for multiouputs and I read mesh_MultiOutputs.slim
to understand
his template, but I search to exploit slim surfaces shaders like SwissArmy,
or custom slim template...

My question is :
If I'll render a slim surface shader into pass , will I tweak the .slim file
like a .sl file ?
If yes, it's very tedious !...
How the studios like ILM, Weta, Pixar, etc.. manage this problem ?
It is possible to create my own built in solution ?

Thanks,
PS : Sorry for my English !
gromfx

[m-koperwas]

An "addon" to my previous post....

I tested AOV too in slim with a layer shader, a Pixar's exemple
https://renderman.pixar.com/forum/showthrea...p;highlight=AOV
but It's not what I seek, because it's a shader layer, not
a "basic" shader like Blinn, Velvet, Skin, SwissArmy (Yet!, for sub-scatt).

The .sl is tweakable will say to me ! but how work the TD ?
I can't believe they spend their times to write AOV !

With a "classic" renderer, some clic and the game is over,
with a "RenderMan" renderer, so many time...with the 3 methods
previously listed. Only mesh_multiOutputs.slim is possible
to use in my "pipeline"...(Thanks Mesh !)...but goodbye SubScatt,
and a kind of useful things...

This the end of my reflection, I have forget somethings ?

My true question is :
How PrMan is used in a production pipeline for manage AOV ?

It won't have maybe an answer, seeking TD's tips is madness,
but I don't work on a single image, do-it-yourselfing is prohibited...

I wait impatiently your opinions on this subject....

Sincerly,
G-Rom.Fx

PS : Sorry for my bad English

[joojaa]

Umm i think you are missing he point of slim templates! The idea is to make a tcl scrip that inject certain parts into a sl file wich is then compiled for rendering, then can use it inside slim clickety click, and build on top of that.

Most of the features are allready availeble inside slim. All you need is to isolate the parts bahind a AOV color variable. Altough to be honest i would rather se the aov feature incorporated into the additive fx template for a bit easier acces, but maybe hats a thing for me to do. But as of now its not that bad a hastle.

But yeah writing your own blocks is the fastest way up to speed. Then all you need is to figure out what pieces you most likely are going to need.