Resizing textures with alpha

NAIMA

Hi , I usualy like to work on large image pictures for textures but then many times I need to resize for game engine fitting and when I have a alpha sometimes it messes up all the borders and layers... how can I do to preserve the alpha at the best when resizing?

cryrid

If it's Photoshop, you could try experimenting with the interpolation of the resize (at the bottom of the resize window, there are five options such as bicubic sharper, nearest neighbour, etc). It should be a quick enough test to see if any of them works better than the default (though if you wanted one channel interpolated differently than the rest, you may have to have a copy of it in a new document, resize there with the different setting, and then paste back).

NAIMA

For the texture is ok I mean for the alpha , I usually have some problems for the alpha selections getting messed up usually and is especially valid for the intricate foliage alpha ...

NAIMA

Other techs?

Noors

Example ?
Is this 1 bit alpha ?

I don't think there's any magic beside using photoshop resampling algorithms.
Bicubic messes a bit border pixels but the result is smoother.
Bilinear won't messing up the layer borders and is less agressive than nearest neighbor.
Nearest is the best choice for 1 bit alpha, but it removes pixels lines so it's not always wanted.
Or an extra fancy rescaling algoritm eg Lanczos and B-Spline ?

Or regenerate the alpha from a diffuse afterward ?

Shadownami92

If it's a 1 bit alpha 1 possible way of doing it I guess would be to trace the shapes with vector tools, don't remember how well that worked with Photoshop but it should work in Illustrator or another vector program. then just import the trace into Photoshop as a smart object.

pasha_sevez

Try Photozoom Pro - it will help.