Molflow allows you to create geometries from scratch or to import (and modify) CAD models.

To create from scratch, see this webinar episode:

Creating geometries with built-in tools

To import from CAD, you need to open STL files created by your CAD editor. There are two documents showing simplification trips:

• 2021 seminar by Noah Jens using ANSYS Spaceclaim
• 2014 seminar by Josef Sestak using Autodesk Inventor

The following tricks can help you make simulations and work with geometries fast and simple in Molflow:

• Use only necessary parts in your geometry. Remove flanges, screwholes and mechanical parts that are not hit by particles. Since CAD programs export geometries in form of triangles, one single hole can severely complicate your geometry
• Use solid structures, „inside out”. Molflow only sees facets, and doesn’t know which part of your geometry is solid or empty. (You can define this by the orientation of the facets’ normal vectors). Therefore, instead of defining a cylinder, that has a wall and a cavity, you can only use half as much facets by creating a solid cylinder.
• Once your simulation has run long enough, you can remove parts that are not necessary, ie. which are never going to be hit. Choose Select Hits>0 from the selection menu, then the Invert selection command, that way you will have all the facets selected that are never hit. Then you can remove them.
• And finally: don't forget to collapse!