Edges of transparent PNG

Support Basics & Interface
1

Hi

I’ve done a PNG of some reeds to place near a pond I’m modelling. They look good except for a thin highlight all around the edge (the boundary between my reeds and the transparent part of the image.

Is there a preferred way of dealing with this; I guess it’s a fairly common problem. Image smoothing tools/techniques etc? The effect is not noticable in GIMP, only when it renders in Blender.

Thanks

2

I have noticed this problem as well. I don’t have a work around as of yet. It is almost as if Blender always assumes the alpha is pre-multiplied instead of straight.

http://blenderartists.org/forum/showthread.php?t=139506

3

Yeah, I can sort of appreciate why the edges are there - because of the antialiasing making the boundary between the transparent section and the image less clear cut - but it would be nice if there was some way of reducing the effect.

I noticed that in Gimp if you start from a blank image with just an alpha layer and then draw on top of that, it’s not so bad. But unfortunately that’s not much help when working with existing textures.

4

Hi all,
the .blend from this thread

renders fine for me (2.48, Linux) if I enable “Premul” in the image panel of the texture buttons - does that work for you?


5

Hey, that seems a lot better actually - thanks!

6

Thanks MPPIC, I wonder why Blender does not click that button atuomatically by default when it detects an alpha channel present in a loaded image?