I'm looking for a 3D solid modeling engine/library that works well with the openTK and C#.
I am not aware of any such library, unfortunately. It seems that most such programs use custom implementations.
However, it is possible that something might have been written for the Tao Framework. Since OpenTK is able to interoperate with Tao projects, it might be worth looking there.
Site design by Stefanos A. Icons courtesy of gnome-colors.