I got some comments back on a Revit project I evaluated a while ago. One of their comments was that they could not resolve some of the errors in the model. They said they could not resolve this error: Duplicate Type Marks, their reply: Particular element having different sizes under one type. ????
I got the impression they didn't quite get the difference between instance and type parameters.
So let me give you a simple example that is easy to understand. Take a look at the picture below. These women have loads of properties but we will focus on two. One of their properties is that they are all a woman. So that's a type property.
The size of their mammalian protuberance is different for everyone of them and therefore an instance property.
Have a nice weekend!