Polyscope is a great C++ viewer and user interface for the rapid prototyping and debugging of 3D geometric algorithms.
The key idea of polyscope is to have the notion of structures (e.g. pointclouds, meshes) and quantities (scalar/vector attributes on faces, vertices…).
Thanks to a generic data adaptation framework, polyscope can be used to quickly to display DGtal data such as digital surfaces and quantities like curvature estimation, normal vector fields (thanks to the brand new Shortcuts helpers).
If you want a quick demo, just have a look to the polyscope-dgtal project.