RhinoCommon: geometrical object mouse tool


When you are placing, for example Spot light, rhino allows you to interactively define some geometrical parameters using mouse

If I want to have something like this for my custom light object can I create it in RhinoCommon and is this possible at all?

Yes, you can use the GetPoint class and use the DynamicDraw event to draw stuff.

See http://4.rhino3d.com/5/rhinocommon/html/T_Rhino_Input_Custom_GetPoint.htm
and for an example: