I'm trying to create a track for Assetto Corsa (a racing game) based on a real mountain road that's close to where I live. It's an ambitious endeavour, but I hope to learn a lot in the process - even if I won't eventaully finish the whole road.

What I've already done is: I imported an SRTM elevation file with this excellent plugin which turns it into a georeferenced mesh. I had to delete big parts of this mesh because it was huge, but now I have the mountain ready.

Next I imported an OSM file containing the road in question with a plugin written by the same author. Now I have two gereferenced objects which superimpose perfectly from what I can tell.

Perspective view

Perspective view with the road floating above the mesh

The problem is that, while the mesh is 3D and ready to use, the road is a 2D path. What I want is to have a 3D path of the road (with elevation) which I can then use as the basis of the road for the game as explained in this tutorial.

Top down view

Top down view

I think I can obtain this path by:

  1. Intersecting an extrusion of the 2D road path with the 3D mesh, but how do I do this? I went as far as creating the extrusion, but I don't know how to do the intersection.
  2. Using Knife Project to cut the mesh with the road's projection. Again, I tried, but Blender crashes, so I'm not sure if I'm doing it right.

Any help appreciated.


1 Answer 1


you can do that with the shrink wrap modifier as follows :

original mesh

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enter image description here

Add the shrink wrap modifier :

enter image description here

and you will get this

enter image description here

if the road is not curved enough " didnt follow the mountain exactly " try to subdivide it before applying the modifier

  • $\begingroup$ don't use the subsurf modifier use the subdivide tool "w in edit mode" so you don't lose the details of the road $\endgroup$
    – Chebhou
    Feb 5, 2015 at 22:26
  • 5
    $\begingroup$ The Subsurf is the best way to go, you just need to change the method from Catmull-Clark to simple, in-order to retain details. $\endgroup$ Feb 6, 2015 at 0:08
  • $\begingroup$ Exactly what I was looking for! Thanks for your answer. But now I hit another bump in the road. Pun intended. :-) $\endgroup$ Feb 6, 2015 at 12:20

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