Eliminating white edging / fading on leaves in distance

sriesch

How do I eliminate the white edging around transparency-mapped tree leaves?  This also has the effect of making trees fade from green to white the farther away they are.  See example screenshot, one tree with two instances, each farther back.

 

mjc1016

Iray or 3Delight?

One possible cause...the mask (transmap) isn't quite a perfect fit, so there is a little border of the background of diffuse map (which is probably white) showing.  Make a copy of the leaf map and flood fill the space around the leaf with something like bright pink, neon blue or anything that will stand out.  Then substitute that for a leaf.  If the mask being slightly off is the cause, it will now show that color instead of white. 

Another possible cause (especially in Iray) is that the transmap isn't really black/white...grays will show as translucent spots.   Also make sure that if you are using Gamma correction ON in 3Delight that the map (according to the image editor) is set correctly (should be a 1.00) there.

sriesch

3DL.

Gamma Correction is off.

Good call on the transparency map, that definitely appears to be part of it.  Here's the same render with the (supposedly invisible) part of the image set to to bright red.  I don't know why the most distant tree is entirely red though, since only a fraction of a percent of the image has the red on it, with it being almost entirely green.  Maybe the very first pixel is used and the rest are discarded, and the first one is the one on the edge that is red?

So I guess now I need to come up with a way to easily modify the transparency to correct for this problem on every tree/plant, since manually repaining them isn't practical for more than one or two.  Ideas?  (I'm using GIMP, but I"m pretty clueless about it's functionality beyond the extreme basics.)  I can't really just resize it slightly because it won't line up will, especially with trees that have mult-segmented leaves rather than just a single leaf. 

mjc1016

It's being compounded by the mipmapping of the texture.   The easiest way I've dealt with it...take the GIMP color picker, set it to 'average' and sample the green leaf...then flood fill the background with that color.   At the distance the lack of details won't matter...