Pierre,

Do you want to actually produce a 3D model with a V groove in the design, or do you want to produce a rendered image of what the final carved object will look like?

If you are wanting to just make a rendered image of the final result, I would recommend getting a render program that supports negative displacement mapping.

Maxwell is an example render program that I have experience with using this technique.

You would create a black & white, evenly graduated displacement map from your carved design. This can easily be done in a vector program like Corel Draw. The white center areas represent the point (deepest part) of your V cutter, the black represents the widest part of the cutter. The graduated gray area represents the V taper of the cutter.

The settings in Maxwell for displacement mapping will allow you to simulate the V cut in a very convincing way without the need to actually model the cuts.

For example, I created the text engraving in this ring render with a displacement map (my engraving tool has a round bottom rather than a V shape). I've modeled text engraving in MoI as well - each method has advantages and disadvantages.

Ed