Turning a mesh into a terrain?

Unity Engine
1

I want to make a terrain in a separate 3d application so that I can put roads and such on it easily in the application and I would texture it in the application and everything(the base texture anyways). Maybe I could model the terrain and export it to unity and then I could make the roads ,but export them separately so that there is no chance that I could paint on them with the texture paint tool. What do you guys think? Also back to the main question, can you turn a mesh into terrain?

2

There’s a plugin in the asset store called mesh to terrain that converts meshes to unity terrain.

Then there’s a plugin called terrain 4 mobile that can take a unity terrain and convert it to a mesh, while keeping the first 4 textures from the terrain.

3

Any free substitute?

4

For free substitutes you can try with free Vertex Painter but of course you will not get as good results as with paid tools