UV mapping- and transparency problems

I created a texture in Gimp which has parts that are transparent. When I map it to an object in Blender, the following problems occur:

  • When I open the image in the uv image editor sometimes the image is not being shown in the editor until I move a Vertex. Is this a refresh bug?

  • The image is being shown upside down on the object. Of course I can just turn the unwrapped part in the editor by 180°. But I don’t think this should be necessary. Is this my or Blender’s fault?

  • Some parts of the exclamation mark and the lightning are way too light. Does anybody know why this happens and how to fix it?

  • For testing purposes I created another image in Gimp which is a gradient that goes from transparent (left) to opaque (right). When I map this image to an object in Blender the very left part shows an ugly stripe (2nd screenshot).


The only thing I further found out is that I have problems with any kind of textures with transparent backgrounds. Let’s say I just have a simple line with a transparent background and I map it to an ordinary cube then the border of the line is brightly white.


Its upside down because you’ve uv unwrapped it upside down.
For the white outline try selecting premultiplied in the render / shading / alpha settings instead of the default Sky

Indeed! Premultiplied solves the problem, but in the Texture / Image panel.
Thank you!