[Bf-committers] Color space issues in importers/exporters

[Campbell Barton]

Would be good to hear more on the use case from the bug reporter.

But I think this issue is you may import models ad-hoc into an
existing scene, without that being a key-part of your pipeline.

In that case its not great if you want to load in some model and the
colors look different.

However this could be taken to an extreme, if you consider color
spaces and linking data between blend files with different color
spaces, and this we better not attempt to *solve* IMHO.

On Tue, Dec 30, 2014 at 8:21 AM, Sergey Sharybin <sergey.vfx at gmail.com> wrote:
> Hi,
>
> First of all, I want to be really sure it is a blender issue, not an issue
> of some particular weird working pipeline.
>
> Hence my question here is: how often do you mix software with different
> color pipelines (in regards of 3d model interchange, NOT gading/comping sw)?
>
> It sounds a bit weird to use blender with color management enabled and then
> export scenes to software which wants everything to be in the display
> space. Why not to disable color management in blender then?
>
> Or even, what i the actual (not hypothetical, but practical) issue we're
> trying to solve here?
>
>
> On Tue, Dec 30, 2014 at 1:50 AM, Campbell Barton <ideasman42 at gmail.com>
> wrote:
>
>> As far as I can see the only good solution here is for import/export
>> to handle the conversion themselves,
>> We can have some convenience functions in `mathutils.Color` so py devs
>> can switch between spaces.
>>
>> On Tue, Dec 30, 2014 at 1:40 AM, Antony Riakiotakis <kalast at gmail.com>
>> wrote:
>> > Hello, we have a bug report that claims our importers do not do any
>> > sort of color space correction
>> > for external assets, see https://developer.blender.org/T43025
>> >
>> > The issue should be that most exporters presume srgb color space while
>> > our material definition is in linear space.
>> >
>> > I am not sure if the asset formats have an explicit color space in
>> > their specification but if not we can assume srgb. In that case, we
>> > should make sure to backconvert from srgb to linear when doing
>> > material conversion.
>> >
>> > A quick test importing and exporting an obj from blender has no
>> > issues, but that is simply because blender just dumps the linear
>> > material value to the file, so reimporting will have the previous
>> > value.
>> >
>> > A way to fix this would be to handle it RNA side assume that assigned
>> > colors are considered srgb and convert them internally but this can
>> > backfire. It might be better to take care of it in our exporter files.
>> >
>> > I am sending this to the list because we have a few maintainers for
>> > our various asset formats.
>> > _______________________________________________
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>> > Bf-committers at blender.org
>> > http://lists.blender.org/mailman/listinfo/bf-committers
>>
>>
>>
>> --
>> - Campbell
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>
>
>
> --
> With best regards, Sergey Sharybin
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-- 
- Campbell