STL to SolidWorks: get an editable solid, not triangles
Last updated by the stl2step team
SolidWorks can import an STL as a solid body, but every triangle becomes its own flat face, so the part can't be edited like a CAD model. To get an editable body, convert the STL to a STEP with real faces first (stl2step does it automatically) and open the STEP in SolidWorks: holes come in as cylinders and flat sides as single planes.
Open an STL as an editable solid in SolidWorks
Convert the STL to STEP
Upload the STL to stl2step and download the .step file. The first 3 conversions are free.
Open the STEP in SolidWorks
File, Open, choose STEP (*.step; *.stp) as the file type and open it. SolidWorks imports it as a solid body with real planar, cylindrical, conical, spherical, toroidal and spline faces.
Run Import Diagnostics if asked
SolidWorks offers to check the imported body; let it, it fixes small gaps between faces if there are any.
Edit the body
Use Move Face, Delete Face and Offset Surface on the imported faces, add new features on top of them, or try FeatureWorks (in SolidWorks Professional and Premium) to recognize holes and extrusions as features.
What SolidWorks does with an STL on its own
When you open an STL, SolidWorks lets you import it as a graphics body, a surface body or a solid body. Even as a solid body, every triangle becomes its own planar face: a hole is a ring of slivers, there is no cylinder to select, and the part is slow to rebuild. Feature recognition can't work on it, and editing means remodeling by hand. ScanTo3D (SolidWorks Premium) helps you fit surfaces to a mesh, region by region.
Converting to STEP with stl2step first gives SolidWorks a body made of the real faces, so the hole is one cylindrical face with a radius you can measure and change.
Questions
Can SolidWorks convert an STL to a solid?
Yes, as a solid body made of one planar face per triangle. It is closed, but it can't be edited like a CAD part. Convert to STEP with real faces first for an editable body.
Will I get a feature tree in SolidWorks?
The STEP imports as a single body without history. Edit it with direct-editing tools or try FeatureWorks to recognize features.