MeshLab is a free and open source processing and editing 3D triangular meshes. It provides a set of tools for editing, cleaning, healing, inspecting, rendering, texturing and converting meshes. It offers features for processing raw data produced by 3D digitization tools/devices and for preparing models for 3D printing.
Extensive and useful tool for mesh processing. This Flatpak version is also 3 years more up-to-date!!