How to create custom type in rhino

[Tom_P]

custom objects with rhinocommon are not very handy.
check some other topics before you invest to much end get disappointed.
my guess - visual ARQ is not written in rhinocommon but c++.

@stevebaer

Custom objects are pretty fragile. Simple tasks like moving control points on a curve has the potential to call Replace on the document with non-custom curve geometry resulting in a custom object turning into a non-custom object.

@dale

RhinoCommon’s support for custom objects is not as robust as that of what you can do in C++. I suggest you look into writing custom objects using the Rhino C++ SDK.

about saving and reopening a file:

@dale

Custom objects are saved as their inherited types. For example, a CustomCurveObject is saved as a CurveObject. Any extra data on your derived object should be saved as user data.

When Rhino opens a document, you should watch for objects with your user data and convert them back to your custom object.