[Openexr-devel] Maximum channel name length

[Ton Roosendaal]

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