Here is a texture map I did to help me map things into place

[Synthercat]

GRID-COLORD.PNG (627 Bytes) Viewed 627 times

[binarycortex]

Can you give an example of how you use this?

[Synthercat]

I place in on a mesh (before I use the texture I want to use) and check out for example if the lines are aligned and if the squares are squares or they become stretched

[patro]

thanks for sharing.... nice idea and very useful.

[Meelis]

About the UV map being stretched,
what's with that in blender when hi geometry object get's stretched uv map and low geometry object not.
Some numerical accuracy i guess

[xray]

About the UV map being stretched,
what's with that in blender when hi geometry object get's stretched uv map and low geometry object not.
Some numerical accuracy i guess

You mean a high geometry by subdivision modifier ? For this situation you could try to enable 'Subdivide UV's' in the subdivision modifier or its due to a bad modeled topology.

[Meelis]

I ment with all modifiers applied and still that problem with hi geometry objects.
Is it halfe of spere, or square or more complex object and hi-poly small object (verteks close eachother)
Or even square rotated hi-poly plane and u don't get not even close to square uv layout in uv-editor.

Some faces will overlap in uv-editor or will have wrong scale and therefore they get same pixel color many faces together,
and then u had maybe 30 pixels in texture for 1 cm area of many faces who get same color assigned in row even if visually looks uv layout ok over many pixels of texture data.

Even paralel edges are not paralel and so on.

So it's best to uv map before subdividing

Only few examples of wrong calculated uv layout
http://www.youtube.com/watch?v=USye4X_hzdA
http://www.youtube.com/watch?v=gCMqMRWIzDE

[xray]

So it's best to uv map before subdividing

Well it depends on your workflow, Ill never apply subdivision modifiers to an object, so you can do your uv mapping whenever you want. Ill let the exporter do the work of applying.

To your other sentences I didn't understood if you have a question or gave just some notes.

[Meelis]

One thing was stretched uv texture, looks like same pixel row will be repeated over and over.
Anyways that was Blender related problem, not LuxRender