Projecting a 2D road onto a 3D elevation mesh 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 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

I think I can obtain this path by:


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

original mesh





Add the shrink wrap modifier :



and you will get this



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