Treat the STL as a mesh
STL has no reliable unit declaration. CADProps measures STL coordinates as millimetres. Confirm a known dimension before converting if the scale matters.
CADProps · CAD tools
Convert STL to OBJ Online: Mesh to Mesh
Convert an STL triangle mesh to OBJ. The conversion does not recover a precise CAD solid or add reliable units.
No account required
Temporary workspaceCAD processingBefore you use the result
Know what you are looking at.
Convert STL to OBJ when another mesh tool expects OBJ. Both files are triangles. This does not turn a mesh back into a STEP solid.
Convert STL to OBJ
Choose OBJ and download the mesh. The triangles are copied into OBJ. Materials, textures and a CAD feature tree are not created.
Do not expect a solid
An open or inconsistent STL stays a mesh. Volume, if shown, is an approximation and only applies to a closed, consistent mesh. Use the original CAD or STEP file when you need an exact solid.
Questions about this task
Know the limits.
Can I convert STL to OBJ online?
Yes. Upload an STL file, choose OBJ and download the mesh.
Will STL to OBJ create a STEP solid?
No. OBJ is still a triangle mesh. Converting the mesh does not reconstruct precise CAD curves or a solid model.
Does the OBJ file gain units?
No. Neither STL nor OBJ declares a reliable unit. CADProps assumes millimetres when it measures these meshes.
Related reading
Checks that help with this file.
MeasurementOBJ Mesh Units and Volume: Check Scale and a Closed Shell
OBJ does not declare reliable units. See how millimetres are assumed, when mesh volume is only an approximation, and why OBJ is not a CAD solid.
Read the guide →
MeasurementDo STL Files Have Units? How to Fix mm vs Inch Scale
Understand why STL coordinates do not reliably declare physical units, diagnose mm-versus-inch scale errors, and verify dimensions before printing or manufacturing.
Read the guide →TroubleshootingSTL Volume Zero or Missing? Check the Mesh Is Closed
Diagnose STL files with zero, missing or unreliable volume by checking watertightness, inconsistent faces, units and export quality before calculating mass.
Read the guide →