Gmsh

Gmsh is a finite-element mesh generator developed by Christophe Geuzaine and Jean-François Remacle. Released under the GNU General Public License, Gmsh is free software.
Gmsh contains 4 modules: for geometry description, meshing, solving and post-processing. Gmsh supports parametric input and has advanced visualization mechanisms. Since version 3.0, Gmsh supports full constructive solid geometry features, based on Open Cascade Technology.
A modified version of Gmsh is integrated with SwiftComp, a general-purpose multiscale modeling software. The modified version, called Gmsh4SC, is compiled and deployed on the Composites Design and Manufacturing HUB (cdmHUB).
Interfaces.
Various graphical user interfaces exist that integrate Gmsh into their workflow: