On the following picture you see an object painted in Christmas colors.
When I export it as an .obj file and open the latter in Meshlab the colors look this way:
The same colors appear on Sculpteo 3D player. They are much darker, and green has become even black.
So the question is : Why? What's wrong with the export?
Peter
Well, I think I found the answer by myself:
It's well known that the colors we see on a Blender rendered image are not the colors we have given to the material. Generally speaking this is due to World's impact. Blender exports in .obj format without taking in view this factor. It does not export the colors you have set in advance, but the colors they change to, when the impact of environment is not there. So even if you open your exported .obj file with Blender you will see your mesh with changed colors (darkened). So in order your .obj file to open the mesh with desired colors lighten them in Blender before exporting.
:)