OSG Exporter - Texture seams somehow have alpha

[JvdBosch]

Michael,

WALL
Thanks for looking at the model. I see now there is indeed a alpha channel in the texture, my bad! This was no issue in previous versions of the exporter/MAX/Vizard using the same textures/models. That's why I didn't suspect the problem to be with the texture.

When I set the exporter to not export opacity maps and use DXT1 it still exports the alpha channel within the diffuse texture image? I guess this behavior has changed since MAX2013 or the new exporter or the latest Vizard? That could explain it, since I used this setting in earlier versions without this problem.

TREE
Regarding the tree, I'm using a GTX680 with the latest drivers. The multisample alpha was and is working fine. The lines are the biggest problem. You say tiling is the answer, so I enabled it. But then you see lines on the top of the tree from the repeating of the treetrunk. See the picture below.

Why is tiling an issue? It never was with previous versions... I find it peculiar to have to set tiling to 0.98 or so to solve a problem which did not exist previously. My complete model has several hundreds of objects with a non-tiled texture. There must be a better way to solve this problem.

Thanks,

Jaap

[Veleno]

Hi Jaap,

Wall:
■ Setting the exporter to DXT1 does appear to be converting alpha channels to 1 bit alpha instead of discarding them, which is odd. The compression ratio still appears to be correct for DXT1. I'm unsure whether this is functioning as intended.

■ Unchecking opacity under maps prevents max from exporting any maps placed in the Opacity slot of a material, which can also be used for transparency.

■ In general, I'd recommend avoiding alpha channels in maps that don't need them. When looking at a model in Inspector, the texture panel will show the format as RGBA if an alpha channel exists for the texture. If not, it will show RGB instead.

Tree:
There are a few ways to fix the issue:

■ Max Method: I've attached a maxscript that will loop through all scene materials (Standard and Standard contained in a multi-material), check for diffuse and opacity maps where tiling is disabled, and if so apply the above tweak. To use it, go to Maxscript -> Run Script... and select Jaap_TweakTiling_2012-01-03.ms.

■ OSGT Method: Save transparent file as OSGT. Open up the plain text model file in your favorite text editor, then use Find and Replace to replace all instances of CLAMP_TO_BORDER with CLAMP_TO_EDGE (case sensitive).

■ Vizard Method: Loop through all textures on the transparent model, changing all tiling that is currently viz.CLAMP_TO_BORDER to viz.CLAMP_TO_EDGE. See the Texture Wrapping entry in the help docs.

The way the exporter currently functions is consistent with how max handles them, at least as far as the diffuse texture goes. However, it does seem like it would be more beneficial, especially in cases like this, to include an option to repeat the texture's edge pixels instead.