.NET Geometry Library?

Question

Does anyone know of a good (efficient, nice API, etc.) geometry open source library for .NET? Some of the operations needed: - Data Structures - Vectors (2D and 3D with `float`s and `double`s) - Lines (2D and 3D) - Rectangles / Squares / Cubes / Boxes - Spheres / Circles - N-Sided Polygon - Matrices (`float`s and `double`s) - Algorithms - Intersection calculations - Area / Volume calculations

Answer 1

https://github.com/mcneel/rhino3dm

Alternatively, look into using Unity (https://unity.com/).