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Participant
November 18, 2016
Question

Transparency on batch exported artboards

  • November 18, 2016
  • 1 reply
  • 452 views

Hello,

I have this issue with exporting artboards for textures, in textures you usually use all channels in the RGBA format and therefore you need the alpha channel intact. When batch exporting with 'Artboards to files...' you do have the option to use TGA, but the alpha data is always discarded, no matter if it is loaded into the actual alpha channel for the whole PSD file or if it is actually transparent from the layer masks in the artboard layers.

I am currently using a workaround with the PNG format to fix the PNG compression bleeds when using the RGBA data in a shader, but it is an unneccessary cost on shaders to do the math there when the data need not be compressed/corrupted in the first place.

It's an otherwise good feature for automating shader structures where you usually have a set of images for different shader features, and I don't see why you would have to go through another process ('Artboards to files...') to get the TGA output. You get transparency on PNGs so that exporter actually has support for the alpha, though this is not through the alpha channel, rather the layer alpha. One of those functions is redundant, and judging from which one works better I think it is the 'Artboards to files...' feature.

Optimal for this workflow would be if it actually took the alpha channel in consideration, since the RGB data need not necessarily match the alpha, depending on how it is used in a shader. Is there possibly being done work on this currently? since it's a pretty new feature it could use some polishing to consider the channel data.

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1 reply

Participant
January 6, 2017

I revisited this issue now when i converted the whole solution to linear rgb and found a working export solution with tga and alpha:

1. Export => Artboards to files...
2. Important to use 'Include Overlapping Areas' - this will include the actual alpha channel, so it has to be prerendered in the workflow

3. Format 32bit tga, though it should export nicely now with anything else using the actual alpha

Works perfect with current Unreal 4.14.2 and by artboard naming conventions you can get it to autotag all textures as correct interpretation for how they are handled. Only downside is that 'Artboards to files...' is very slow when it parses through *all artboards+content* for each artboard in this mode but it totally makes up for the time saved on handling files.