Hey, This is Siddharth Kumar. I have been working on the Boost.Geometry library for the past 2-3 months. I would like to propose a project idea about adding features for 3d-geometries, especially polyhedral surfaces which includes:- 1. Defining a geometry for the polyhedral surfaces. 2. Read and write features for the polyhedral surfaces. 3. Defining functions for the properties of polyhedral surfaces like volume, surface area, etc. This implementation will help in the direct use of the geometry in such algorithms, which are not yet implemented for the 3d-geometries or don’t provide compatible results when working with 3d-shapes, as they give points as an output rather than taking a geometry. For example- The convex hull https://github.com/boostorg/geometry/issues/683 doesn’t handle 3d geometries correctly, because there is no 3d geometry defined that can handle the result of the algorithm. I have already submitted a PR https://github.com/boostorg/geometry/pull/789 (yet to be merged), which defines the geometry for polyhedral surfaces, and also includes wkt read and write features, I am willing to work on other properties of the polyhedral surfaces as a project for GSOC 2021. I am looking for a mentor who is willing to guide me in this project. Thanks