Open SolidCraft above, then drop a STEP file on the window to try it. SolidCraft reads STEP with its own reader, written from the public standards, so you don't need any other CAD program installed.
Does SolidCraft support STEP files?
Yes, both ways. According to SolidCraft's documentation:
| Direction | What SolidCraft handles |
|---|---|
| Import | STEP AP203, AP214 and AP242 (.step, .stp): solids, assemblies, units, names and colours |
| Export | STEP AP242 with body names, colours, and components as assemblies |
The same import and export table also covers IGES 5.3, 3MF, STL and OBJ. FreeCAD (.FCStd) and Rhino (.3dm) solids import through a converter in the desktop app and CLI.
How to open a STEP file
There are three ways in, and they behave slightly differently:
- Open as a new design. Use File → Open and pick a
.stepor.stpfile. SolidCraft starts a new design with the file's bodies. - Insert into the design you have open. Use File → Insert STEP…, or SOLID → INSERT. The file's bodies are added to your current design.
- Drag and drop. Drop a STEP file on the window. If your design already has features, the file is inserted; if it's empty, the file opens as a new design.
From the command line, solidcraft part.step opens a file, and solidcraft-cli eval part.step measures an imported part. If you use SolidCraft with Claude, the MCP server's open tool does the same thing (see our SolidCraft MCP setup guide).
What happens to the file after import
The STEP file becomes an Import feature on the timeline. The file's text is stored inside your design, so the design still opens if you delete or move the original file.
Every import comes in as a new component named after the file. Import bracket.step and you get a component called bracket, so its bodies never mix with your own. A STEP assembly keeps its structure: each part becomes a nested component, and a part used in several places becomes one component with an occurrence for each place.
Imported assemblies are rigid at first. Moving the import moves everything together. To joint the parts one by one, right-click the component and choose Unlock Contents. Undo removes a whole import in one step.
You can keep modeling on top of the import: fillets, holes, shells and cuts sketched on its faces all build on the imported bodies. What you don't get is the original feature history from the program that made the file. That is a limit of STEP itself, not of SolidCraft.
Fix 1: the part is lying on its back
Many CAD programs write files with Y pointing up. SolidCraft uses Z up, so those parts arrive lying on their back.
- After opening the file, accept SolidCraft's "Stand it up" offer. It turns the import a quarter turn so Y becomes Z, and the whole assembly turns together.
- In a script or MCP call, pass
"up": "y"when you import. The import and the turn are one undo step.
Fix 2: every body has a strange name
Some programs name each solid after the last feature that made it, so you end up with bodies called Cut-Extrude3. SolidCraft's import takes a names option:
| Option | Bodies are named after |
|---|---|
solid (default) |
The solid's name in the file, or the part's name if the solid has none |
product |
The part that holds the body |
instance |
The assembly occurrence, such as Post-2 |
For example, a script can insert a Y-up assembly with readable names in one step:
{"command": "file.insert_step", "params": {"path": "frame.step", "up": "y", "names": "instance"}}
How to export a STEP file
Export writes STEP AP242, keeping body names, colours and your component tree as an assembly. Scripts, the CLI and the MCP server use the file.export command with a .step path. With the CLI you can build a part from a recipe and write STEP in one line:
solidcraft-cli run examples/bracket.json --out bracket.step
If you also fill in File → Design Properties…, the author, organization and description go into the STEP file's header.
Need a mesh for 3D printing instead? Use File → Save as mesh… for STL or 3MF. New to SolidCraft? Start with the SolidCraft tutorial, or get the desktop app from the SolidCraft download page.