STLBenchFree online STL to SolidWorks converter
STL to SolidWorks — import it as a solid, not a graphics body
Convert the mesh to STEP here, then open that in SolidWorks: it arrives as an imported solid body with real cylindrical faces and holes at their true diameter, and there are no import options to get wrong. Opening the STL directly gives you a graphics body you can look at and little else — or, if you force a solid import, a body with one face per triangle that is painful to work in. The page says which category your file is in before it converts anything, and nothing is uploaded.
- 100% free
- No signup
- Real solid body
- Holes at true size
- Nothing uploaded
Drag a file anywhere on this page to open it. F fits the view, W switches shading, G the grid, R spins it.
How to get an STL into SolidWorks
Three steps, and the second one happens in SolidWorks rather than here.
Convert the mesh to STEP here
Drop the STL and read the verdict first: it says how much of the surface came back as real planes, cylinders and cones. That number is what decides whether SolidWorks receives geometry you can dimension or a lump you can only look at.
Open the STEP in SolidWorks
File → Open, pick the .step, and it arrives as a solid body — no import options to get wrong, no facet limits, no knitting step. This is the route SolidWorks is built for, which is why it is the one worth taking.
Check it imported as a solid
The feature tree should show an imported solid body rather than a graphics body, and Mass Properties should return a volume. If it does, you can cut, fillet, mate and measure it. Volume is the quick test: a surface body has none.
Technical specifications
| Reads | .stl — binary or ASCII; also OBJ, PLY, 3MF, GLB |
|---|---|
| Writes | .step — AP214, MANIFOLD_SOLID_BREP, millimetres declared |
| Rebuilds | Planes, cylinders whole or partial, full cones; holes as true circles |
| Not rebuilt | Fillets, spheres, spline surfaces, threads — left as facets |
| In SolidWorks | Opens as an imported solid body; no import options to set |
| Not produced | A feature tree — that history did not survive into the mesh |
| Gate | Recognised surface share and verdict shown before converting |
| Closure | Checked: every edge used by exactly two faces before you download |
| File size | No fixed limit — past 100 MB you are told what it will cost this tab, then it opens |
Frequently asked questions
Why can I not edit the STL SolidWorks just opened?
Because by default it comes in as a graphics body: a mesh SolidWorks will display and let you measure crudely, and nothing more. The import dialog does offer solid body and surface body instead, and for small meshes those work — each triangle becomes a face and the result gets knitted. The reason it is not the default is that the arithmetic scales badly: a mesh with tens of thousands of facets becomes a body with tens of thousands of faces, which is slow to open, slow to rebuild, and awkward to select anything in. That is the real problem, and converting to STEP first is the way around it.
What is the facet limit?
There is no single published number to quote, and anyone who gives you one exactly is guessing. What is reliably true is that solid-body import from a mesh degrades with facet count, and by the tens of thousands it is slow enough that people abandon it. A modest print export — a bracket at a few thousand triangles — usually imports fine. A part exported at fine resolution usually does not, or does and is unpleasant to work with afterwards.
How is the STEP from here different?
It has fewer faces because the faces are real. Triangles that turn out to sit on a common surface are collapsed back into that surface, so a bore that arrived as sixty strips leaves as a single cylindrical face with a circle at each end — the form it had in the CAD before anyone exported a mesh. SolidWorks opens that quickly, and selecting the hole is one click rather than a rubber-band around two hundred slivers.
Will I get a feature tree?
No, and nothing can give you one. A feature tree is design history — extrude this sketch, then cut that hole — and none of that survived into the mesh. What arrives is an imported solid: geometry you can measure, mate, cut and build against, but not a parametric model you can drive from a sketch. FeatureWorks can attempt to recognise features on an imported solid, and it does better on a body with real cylindrical faces than on a facet body, which is another reason for the conversion.
What about ScanTo3D?
It is the right tool for a genuinely scanned surface, and a different job from this one. ScanTo3D fits surfaces to point clouds and meshes with the assumption that the shape is free-form. If your mesh came from a scan, that workflow is where to spend the effort. If it came from a modelled part — most STLs do — recovering the planes and cylinders it was tessellated from is faster and more exact than surfacing it.
Does anything get uploaded?
No. The recognition and the STEP writing run in this tab, in a worker thread. Nothing about your part crosses the network, which is worth caring about given that the parts people convert for SolidWorks are usually production parts under NDA.
Why the direct import disappoints
SolidWorks can open an STL, which is exactly why this trips people up. The file opens, the part appears on screen, and then nothing works: no face selects sensibly, no dimension attaches, Mass Properties has nothing to report. What arrived is a graphics body — a mesh being displayed, not geometry being modelled. It is the honest default, because the alternatives are worse than they look.
The import dialog will offer to bring the mesh in as a solid or surface body, and on a small mesh that is fine. The problem is arithmetic: every triangle becomes a face. A print-quality export runs to tens of thousands of triangles, so the body has tens of thousands of faces, and a modelling kernel that has to sew and track all of them gets slow in a way that does not recover. Selecting the wall of a hole means catching two hundred narrow faces. Filleting an edge is not possible, because the edge is a chain of hundreds.
The conversion here attacks the face count at its source. Triangles whose normals agree are grouped into regions, and a region that fits a plane, a cylinder or a cone is rebuilt as that surface — one face where there were forty. What SolidWorks then receives is a file of the size and structure it was designed around, and it behaves accordingly: it opens in seconds, rebuilds without complaint, and lets you pick features instead of fragments.
What it does not receive is design intent. There is no feature tree, no sketch to drive, no parameter to change — that history is not in the mesh and no conversion can invent it. What you get is measurable, mateable, cuttable geometry, which for fitting a new part to an existing one is usually the whole requirement. The mechanics of the rebuild are explained on STL to STEP, and STL to CAD covers which meshes are worth attempting at all.
Where the conversion happens
Every number on this page is worked out by JavaScript running in the tab you are reading it in. The model you open is read straight off your own disk — it is never uploaded, logged or kept, which is also why these tools carry on working after you disconnect from the network.
The clause worth repeating on this page: parts converted for SolidWorks are production parts, and the commercial services that do this conversion do it on their servers. Here the recognition and the STEP writing run in a worker thread inside this tab, and no request carrying your geometry is ever made.