> my approach is to just examine box-like TS voxels (like
> the APC) and see what rough obvious matches I can see.

> Possibly a wider statistical analysis can help, but that
> would be time-consuming to script



Good news guys, i'm spotting the first matching indexes on a modified APC voxel.

Here is what I did :
I used a test slab with color index 70 (an olive-green color).
Then I edited the APC voxel with Olaf's new tool vxl>txt.

This way I had an APC in a uniform color, not influencing the colorshift caused by the normals.

I've allready pinned down 3 normal indexes and it promoses to be easy... more in a few hours... :D