It's possible, but a bit tricky:
First of all, you need to get the coordiantes where the player clicked, for example:
on "LeftClick" {
var x = Game.MouseX;
var Y = Game.MouseY;
}
Then, for that Coordinates you have to create all the regions and stuff you need on the Fly, for example for the Cube you would do something like:
Scene.CreateEntity("cube");
var cube = Scene.GetNode("Cube");
Now you can set the X and Y Pos, size, etc. . Same thing goes for regions. You can do all that stuff in a script and attach it to your game / scene whereever you want to load it.
Greets,
Spellbreaker