AUTOMOLD3D · BLOG
STL vs OBJ vs 3MF for 3D Printing and Mold Making
Choose the file format that preserves the information your workflow needs, then confirm scale and mesh health before making a mold.
STL is widely accepted for printable triangle meshes but carries little context beyond geometry. OBJ can carry separate mesh data and material references, while 3MF can retain richer print-oriented information depending on the software that created it.
For mold generation, the critical requirement is a usable mesh with the correct scale and topology. Convert CAD or scan data deliberately and inspect the result rather than assuming a file extension guarantees a watertight object.
Use the format your next tool supports reliably, and archive the original project file separately. Once geometry is exported to a mesh, confirm dimensions and surface detail before using it as the source of a cavity.