Good afternoon to all.
Is it possible to create a material that chose the rotation of the texture according to face lenght?
Like a wood material to apply to this table and chairs.
Thank you
AFAIK no, unless you use OSL scripts.
I don’t know your current needs, nor the render engine you are using, though I’d suggest to use UV map with ‘Smart UV Project’, then manually rotate 90° what doesn’t match.
paolo
Yes, UV’s gives me some control. I’m using Cycles. Now that I’m taking the first steps with node materials, you present me with the OSL scripts. I got overwhelmed now!! 
Thank you for the tips!
I know nothing about OSL, myself :o
paolo
in this case, unless you program a specific OSL script for each object for generating the coordinates with the correct tangent vectors, you’ll be better working with the UVmaps as sourvinos pointed out.
There are other possible ways, like using some bitmap/vertexpaint/etc to tell the shader the orientation of the veins, but any of them require simple coordinate transformations that can easily be accomplished just with nodes. Still, you need to suply the shader the tangent info (simply the x axis from the UV) 