I first started working on this for my Look Cursor but have decoupled it to make it easy to use in other mods. I've also combined it with bits of Nash's Radius Debug mod, particularly the wireframe cubes as indicators.
What is it? Put it this way - does your mod have a need to the player to point to something specific? For example do you have minions that the player can tell to target certain monsters, or go get certain pickups, or to guard a certain area? Or to call an airstrike and have the player point to a specific area to target? This mod gives the player a 3d cursor to point to something specific.
To use it is pretty easy:
create a class that inherits the MWR_Cursor3dInv class
override the functions DoAfterEnable, DoWhileEnabled, DoBeforeDisable to tell what to do before, during, and after cursor activation: put calls to your mod here
give the player a way to call the EnableCursor and DisableCursor functions. Could do this from an event handler or from a weapon or whatever works for your mod.
give this new class to your player (it's an inventory item)