[Openexr-devel] Multi-layer multi-pass files

[Ton Roosendaal]

Hi OpenEXR team,

I'm wrapping up work for our next Blender release, which supports  
multi-layer multi-pass rendering now. We will make use of openexr files  
for writing/reading an entire set of layers/passes in a single file.

In May this year I've noticed a bug in the channel naming, which didn't  
suppport longer nested names than 32 characters in total. I didn't get  
an answer to that, is this fixed?

Other question; is there a naming standard for layers/passes in files?  
Or, how can we make sure that such files open nicely in other  
applications that support openexr?

Thanks,

-Ton-

On 12 May, 2006, at 13:06, Ton Roosendaal wrote:

> Hi,
>
> It looks like channel names in files are truncated to be 31 chars  
> (plus trailing zero) maximum. That seems to be defined in ImfName.h.
>
> In Blender we make use of the features as described in  
> ImfChannelList.h, for image files with many channels to group them  
> into nested layers. Unfortunately the maximum of 32 chars seems to be  
> for the total name, not for the individual nexted parts.
>
> For example; in Blender you can define per render command:
> - Layers (geometry based, like foreground/background)
>   - Passes (shading based, like per Lamp or Combined)
>     - Channels (R,G,B,A or X,Y,Z, etc)
>
> I get errors reading back files with a channel named like:
>
> Characters_and_platform.Combined.R
>
> Which is just 34 characters...
> So, is this limited naming behaviour as expected?
>
> Thanks,
>
> -Ton-

------------------------------------------------------------------------ 
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Ton Roosendaal  Blender Foundation address@hidden  
http://www.blender.org