Possible to make player editable terrain while in game?

Would it be somehow possible to allow the player to change the terrain? Like in Wurm or Xsyon (two small indie games)

I know certain games specifically built their engines so the terrain was easily modifiable by the players in game.

But can Unity do this already?

Something to allow the player to have control over raising and lowering the terrain, however to do so would be very time consuming, 1000x longer than it takes for the world designer to change things.

Is this possible to do without minecraft cubes, using the Unity engine??

Before I even get into attempting to learn how to code this I wanted to see if it was even possible in the engine.

I’m assuming things like allowing player constructed buildings via modules they slide together is possible, but I am not so sure about this terrain thing…

Thanks in advance.

It is possible. A few people on this forum have done it before.
Unfortunately, I can’t remember who it was that did it.

Here’s 2 examples of modifying unity terrain:
http://blog.almostlogical.com/2010/06/10/real-time-terrain-deformation-in-unity3d/
http://forum.unity3d.com/threads/129876-real-time-Destructible-Terrain-implementation
But its quite slow…

Might be good idea to try your own mesh and raise/lower the vertices yourself,
check the unity procedural examples for mesh deforming…

Thanks for these

What do you mean it is quite slow? poor fps?

Those looked pretty good and exactly what I was looking for. However more along the lines of a player digging holes or raising terrain by making dirt mounds.

Creating my own mesh would probably work easier but not really feasible for modifying any part of the terrain in the game world.