Can I edit an existing terrain?

Hello

I bought an terrain in the asset store which was created with World Machine. In the demo project there is no world machine file but a heigthmap.raw file. I would like to change this terrain, edding some extra terrain on it. Is that possible? If yes, how? I managed to export the terrain as obj file but that's all that I managed. When I imported it in e..g. Bryce, it looks strange

 

I'm not sure on this, but I think because .raw is an image type file, unity uses the black/white information as height information to create a terrain mesh. Example, black is high, white is low. So I think to edit the terrain, you would need to edit the .raw file in Gimp or Photoshop add black or white to create new terrain.
Maybe this will help.http://docs.unity3d.com/Manual/terrain-Height.html

 

What you can do, is create a terrain, and then import the .raw file as its heightmap by clicking on the little gear icon in the inspector, and selecting "import raw". Then, use the Unity terrain editor to your heart's content! When you're done, you can export the modified heightmap in that same section of the editor!

Unfortunately, this will not update the OBJ. You will have to either continue using the terrain engine, or somehow generate an OBJ file from the heightmap externally.