Point'n'click terrain and optimization

[plaristote]

-use a plane for mouse collisions and cast a ray up from the point where the mouse/plane collision happened. You could have a few planes and select the point that was nearest (a bit crazy idea, but could work)

That’s actually exactly what I used to do before.
The problem was that to pick the y position of the plane, I made an average of the y position of all the waypoints of the floor. So when the terrain was getting bumpy, or when the average was completely off for some part of the map, the precision issues were very noticeable (or downright ruining the experience of the game in the worst cases).
But yeah it was pretty fast !

-use octree

From what I can gather on google, this looks like a good way to implement the cutting of the terrain.
This topic might help, if I can port the code to C++:

Egg Octree

Egg Octree This code allows to split an Egg object and build an octree. What is an Octree ? (from Wikipedia) An octree is a tree data structure in which each internal node has up to eight children. Octrees are most often used to partition a three dimensional space by recursively subdividing it into eight octants. How does this implementation work ? Give it an egg object, with a vertexpool and a list of vertices. You also give a minimum cell size. A new egg object is created, with a tree con…

Thanks a lot for all the details ! It helps a great deal !
This looks very promising: I’ll check out the octree, and if I get it to work properly I’ll come back with a C++ port of the ‘Egg Octree’ script.