SaveImage node not capable of RGBA?

General9
1

Hi,

I’m currently working on a project where i need to take a texture and transfer it to another model.
This texture needs to be RGBA but saving with the “SaveImage” node will sort of “bake” in the transparancy
into the RGB and skip the whole “A” channel.

Is there any solution to this?

2

Hi Kevin,

Please let me know in what format you are trying to save it? It should work well with png and tiff formats.

3

I’ve tried to save the file with every possible export format in wrap, tiff and png included. To not cause any miss understanding, the transparency is saved in the file, but not as a channel, which is the problem. This will require me to jump into photoshop and somehow take the transparency information from the pixels and apply it into an alpha channel to then save out. This method takes a long time when processing multiple textures during the day if the alternative is just having an alpha channel in the saved file.

4

Hi Kevin,

Thank you for providing the detailed information. All the work with images will be updated in the new release which we are planning for the end of November 2021.
Until it’s fixed, you can alternatively try using the ReplaceImageChannels node to reorder the channels in the image.

Please let me know if it works for you.

5

Hi, I’ve tried the ReplaceImageChannels and it does what it is supposed to do, as in, I can place another channel in the alpha. But in the end this exports as transparency instead of an alpha channel still, so the node is useful, but not to solve this problem. I’ve accepted that I have to include photoshop in my workflow to convert the transparency to alpha channel for now at least. Though adding a channel for alpha in the exports in the future would be really useful and cut out unnecessary reorganizing steps.

6

Hi Kevin,

Am I understanding a problem in a correct way?

  1. You have a file in Wrap with 4 channels (RGBA), all of each is ok.
  2. When you save it, the Alpha channel all becomes intransparent, and the alpha multiplier is all transferred to color channels?
    For example, if you have on original picture a pixel with #RRGGBBAA = #ff22007a (its full red, a bit green, and a 50% opacity), then the saved image will have a pixel of ##7a1100ff (red and green will be halfed, and opacity will be full)?
    I am trying to find out which formula describes the problem you have.

Currently, in Wrap 2021.11.1, I have completely no problem in saving transparent (RGBA) images as .png. Is a problem with the premulting color channels?