How to convert files from COMSOL Multiphysics
to OBJ?

COMSOL Multiphysics® is a general-purpose simulation software for modeling designs, devices, and processes in all fields of engineering, manufacturing, and scientific research. In addition to using multiphysics modeling for your own projects, you can also turn your models into simulation applications and digital twins for use by other design teams, manufacturing departments, test labs, customers, and more.

The platform product can be used on its own or expanded with functionality from any combination of add-on modules for simulating electromagnetics, structural mechanics, acoustics, fluid flow, heat transfer, and chemical engineering. The add-on modules and LiveLink™ products connect seamlessly for a modeling workflow that remains the same regardless of what you are modeling.

OBJ is a geometry definition file format (.obj extension) first developed by Wavefront Technologies for its Advanced Visualizer animation package.

The OBJ file format is a simple data-format that represents 3D geometry alone — namely, the position of each vertex, the UV position of each texture coordinate vertex, vertex normals, and the faces that make each polygon defined as a list of vertices, and texture vertices.

Vertices are stored in a counter-clockwise order by default, making explicit declaration of face normals unnecessary. OBJ coordinates have no units, but OBJ files can contain scale information in a human readable comment line.