[Bf-committers] Re: render passes & workflow

[Ton Roosendaal]

Hi,

OpenEXR was designed to be multi-layer multi-pass. And since it's an  
open format, something we should support first, and discuss with the  
ILM team if we can somehow standardize naming for layers/passes. They  
then can take care of promoting this among the other application  
developers, like for the plugin in Photoshop.

For the time being, I can at least ensure Blender reads/writes such  
multi-exr files well, also for image window and image-input nodes.

Some interested developer then can also look at adding the  
Combuston/3DS RPF (Rich Pixel Format) format. Or, also seems to be  
supported: Irix RLA Files (currently already in Blender, in the past we  
added a Z to this (IriZ), but that appeared to be not readable in any  
other program than Blender...).

-Ton-


On 7 Dec, 2006, at 13:58, Roland Hess wrote:

> Almost any article I've read on using pass rendering seems to focus on  
> doing your final renders in passes for greater flexibility down the  
> pipeline. Now, if the rest of your pipeline is Blender's compositor,  
> then it's not an issue. However, if you're using something else as  
> your target -- putting this in with a bunch of other apps, or handing  
> the files off to another "department" for compositing/sweetening --  
> you would want to be able to have all passes saved into a file format  
> straight out of the renderer in which each pass is a layer (per the  
> image editor of your choice) set with the appropriate blend mode flags  
> so that rendered files can be opened in either a still editor or  
> compositing app with layers (passes) intact, blended properly and  
> ready to be tweaked.
>
> Unfortunately, OpenEXR isn't up to this sort of challenge right now --  
> the file format may be able to handle the channels, but there doesn't  
> seem to be support for having those appear in image editors in a  
> useful way. Of course, it wouldn't hurt if Blender could read such  
> files right back in at a later date, allowing you access in the  
> compositor to each channel set appropriately.
>
> On Dec 6, 2006, at 4:33 PM, bf-committers-request at projects.blender.org  
> wrote:
>
>> Now that the basic code work was done, it's time to check on usablity
>> of pass rendering.
>> (No Trip, not usuability of compositor, that's another project!).
>>
>> Two ideas I got in mind now:
>>
>> 1 Make the "Combined" pass (optional) exclusive passes.
>>
>> My assumption is that you only use passes for specific cases, like  
>> only
>> the shadow pass or only the reflection pass. In that case, a composite
>> now is difficult to use when "Combined" has this pass info added (for
>> example blurring shadow).
>>
>> 2 Give RenderLayers two new options:
>>   - Light (Group) override
>>   - Material (incl Node tree) override
>>
>> This option will render everything in the RenderLayer with a specific
>> group of Lamps, and/or with a specific Material. That's a much more
>> powerful way than define a "custom pass", since then you have the the
>> RenderLayer result again with all existing passes available.
>> It also gives a nice use for the to-be-added Python Node shaders. :)
>
> Roland Hess
> IT Manager/Digital Prepress
> Reed & Witting Company
> Pittsburgh, PA
> 412-682-1000
> rolandh at reed-witting.com
>
>
>
>
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------------------------------------------------------------------------ 
--
Ton Roosendaal  Blender Foundation ton at blender.org  
http://www.blender.org