Jointly vs sw2urdf
Both take a SolidWorks assembly to URDF. The difference is how much manual setup you do per link, and what else you get out of the conversion.
| sw2urdf | Jointly | |
|---|---|---|
| Cost | Free, open source | Free trial, then paid |
| Requires native SolidWorks + mates | Yes | No — also works from a mate-less STEP export |
| Joint axis setup | Manual — you place a reference coordinate system and axis per joint | Automatic — inferred from mates or B-Rep geometry |
| Inertia | Read from SolidWorks mass properties (depends on your material assignment) | Computed from geometry with Mirtich's algorithm |
| Collision geometry | Reuses the visual mesh by default | Convex collision generated automatically |
| Output formats | URDF only | URDF, SDF, MJCF, USD |
| Best for | Small assemblies, one-off jobs, full manual control | Larger assemblies, repeated conversions, STEP-only inputs, multi-sim export |
sw2urdf is a solid, free tool if you're comfortable placing a reference axis on every link and only need plain URDF. The manual workflow is covered step by step in our SolidWorks-to-URDF guide. Where it gets slow is scale (an N-link robot means N manual axis placements) and the mate-less case (a STEP export from a client has no mates for sw2urdf to read at all).
Jointly ingests the same SolidWorks assembly (or its STEP export) and infers the joint structure, axes, inertia and collision automatically, then exports to four simulator formats instead of one. You still confirm what a static model can't reveal — joint limits and which joints are motorized — but you're not hand-placing coordinate systems.
Skip the manual work
Jointly does everything on this page automatically: drop in your CAD (STEP, mesh, SolidWorks or Onshape), and it infers joints, axes, inertia and collision, then exports a simulation-ready URDF, SDF, MJCF or USD. The first conversions are free.
Try Jointly free →