I guess I have found the answer on my own. For those who are curious, there is a bug in Gimp 2.10.
The workaround seems to be to remove the alpha channel before using this tool. While there are no transparent spots in the original flat image, apparently the presence of an alpha layer causes gimp to fail to render the cylinder image properly.
Thanks for your reply. It looks like we just posted simultaneously. As stated below, the problem is a bug in gimp 2.10.
I don't get the error if I delete the alpha channel before using the tool. It should not make a difference.
In your case, the files I uploaded were JPG files to keep the size down. JPG doesn't usually have an alpha channel so you wouldn't see the problem.
I tried adding the alpha channel back and the problem didn't come back. So there apparently was something flakey about the original PNG image that had the alpha channel.
Going back to the original PNG, I used Alpha To Selection, then Add Layer Mask(Selection) then Show Layer Mask. This was to see if there was anything on the alpha layer and there wasn't.
If you are curious, I can post the PNG that I can replicate the problem with. It is 6.6MB.
The workaround seems to be to remove the alpha channel before using this tool. While there are no transparent spots in the original flat image, apparently the presence of an alpha layer causes gimp to fail to render the cylinder image properly.
(05-07-2025, 06:44 PM)rich2005 Wrote: Who knows except yourself. I can not reproduce your transparency. This a half scale result (full size png too large to post)
Because there are many settings these screenshots of all the dialogues. How do they compare with yours ?
Note it works best with a square base image . The white image is the top and bottom.
Thanks for your reply. It looks like we just posted simultaneously. As stated below, the problem is a bug in gimp 2.10.
I don't get the error if I delete the alpha channel before using the tool. It should not make a difference.
In your case, the files I uploaded were JPG files to keep the size down. JPG doesn't usually have an alpha channel so you wouldn't see the problem.
I tried adding the alpha channel back and the problem didn't come back. So there apparently was something flakey about the original PNG image that had the alpha channel.
Going back to the original PNG, I used Alpha To Selection, then Add Layer Mask(Selection) then Show Layer Mask. This was to see if there was anything on the alpha layer and there wasn't.
If you are curious, I can post the PNG that I can replicate the problem with. It is 6.6MB.