Approach to define a direction/Join geometry(RhinoCommon)


I use a circle object to represent my custom light source. it’s a directional light so I need somehow to define direction. Usually we just use transformation matrix of object and some base vector. But it looks like there is no way to get ‘transformation’ from Rhino object.
How it can be achieved in Rhino?
I have only one idea: add special arrow-ended line and join it with light gizmo and use this line as a direction vector. If it sounds good then how can I join two geometries or objects into one?

Rhino has a directional light object. Can you just use it?

Also, its possible to create your own custom objects and have them draw any way you want. My first suggestion is much easier…

This is correct for the most part. It is possible to add custom user data to any object. Then when the object is transformed, the user data’s OnTranform member is called - allowing you to maintain a transformation matrix.