what's the difference between VIS component and Visualization

hello.I want to know the difference between VIS and Visualization.Both of them have the presentation and selection.

Kirill Gavrilov's picture

VIS stands for Vtk Interactive Services, it implements auxiliary classes displaying TopoDS shapes within VTK Viewer.
Visualization is the module providing native services on top of low level libraries OpenGL / OpenGL ES / Vulkan. This is the main module used by most OCCT applications, while VIS helps integrating into application already using (or need using for some reason) VTK. It actually uses some libraries from Visualization module.