Can I use those textures to do commercial work or not?
if you read their page
Legal StuffEvery resource provided on texturemate falls under a Creative Commons License, except credit is not required. The stock textures, texture packs, brush packs, and any other resources available for download on this site are completely free and may be used in commercial or non-commercial applications. Credit to texturemate for use of available textures or brushes is appreciated, but not required. These textures may be used in 3D modeling software packages where their appearance is altered, such as Blender, 3DS Max, Solidworks, CAD, or Second Life. They may also be used in scrapbooking applications. The only exception is that they cannot be redistributed commercially in their unedited form. These textures cannot be re-packaged and resold without significant modifications to their appearance. Brush packs may be used to create unique images in Gimp or Adobe Photoshop, but they cannot be redistributed without being significantly edited. Any resource on texturemate may be linked to when sharing information or resources to others.
I couldn’t find that. >.> But thanks.
Looks like they don’t understand Creative Commons very well. The license they picked (CC-BY) does explicitly grant you the rights to “to copy, distribute and transmit the work” and it doesn’t allow to just add any stipulations on top of that. Either the textures are licensed under CC-BY and can be redistributed even in their unedited form, or they come with their own license that isn’t CC at all. (like the cgtextures license)
EDIT: Having said that, they could be distributed under a dual license, one being CC-BY-NC and one being for commercial uses with the aforementioned restrictions.
As it is now, however, the licensing of the textures is unclear. At no point is it explicitly stated the textures are licensed under CC-BY. Arguably, the textures are licensed under the terms described and the link to CC is just misplaced.