Creative workflows
SolidCraft: Check Your First CAD Part Before Using AI Product Images
SolidCraft is an independent parametric CAD tool. Build a small measurable fixture, check the saved design and export, then separate engineering geometry from generated presentation images.
SolidCraft is an open-source parametric 3D CAD application, with a desktop app, browser app, command-line tools and an MCP server for agents. Its editable geometry and feature timeline make it useful for defining a part. It is not an image model, and SJolt does not expose a SolidCraft CAD endpoint.
Start with one simple part whose dimensions you can verify independently. Once the CAD result passes, a rendered view can become a reference for a separate presentation-image workflow. Keep the measured design as the authority for shape, dimensions and fit.
Find the official project and preserve the old design
The official project links solidcraft.io, docs.solidcraft.io and the tangency-labs/solidcraft repository. Older links may use bherbruck/solidcraft or the former SolveCraft name. Use the project’s release page to identify the exact package instead of treating a similarly named download site as authoritative.
At this October 23 check, the latest release is v0.20.0, published at 00:51 UTC. Its release notes say that saved designs use format 31: this version opens earlier designs, but v0.19.0 and older cannot open a design saved by v0.20.0. Keep an untouched copy before saving an existing project with the new version.
Choose the package for your operating system and architecture, and retain the version with your project notes. The release includes a separate macOS CLI package; having the desktop app does not by itself put solidcraft-cli on your shell path. This guide reviewed documentation and example syntax without installing or executing the application.
The project describes itself as early and usable for simple parts. Its public reference checks cover a specific set of models, not every geometry or downstream workflow. A small acceptance fixture is more useful than assuming that a familiar CAD operation implies complete compatibility with another editor.
Build a rectangular fixture with an analytic answer
The tagged scripting guide uses a commands array containing the same command IDs used by the UI. The following fixture retains its sketch and extrusion steps while omitting the fillet, so the expected volume stays easy to calculate. Save it as block.json in a dedicated test folder.
{
"commands": [
{
"command": "sketch.create",
"params": {
"plane": "XY"
}
},
{
"command": "sketch.rectangle.two_point",
"params": {
"p0": [
0,
0
],
"p1": [
40,
30
]
}
},
{
"command": "solid.extrude",
"params": {
"distance": 20
}
}
]
}solidcraft-cli run block.json --out block.stepWith millimetres as the working units, a 40 × 30 × 20 solid rectangular prism has volume 24,000 mm³ and surface area 5,200 mm². These are calculated expectations, not measurements from a SolidCraft run. Confirm the unit setting and measure the result before declaring the fixture passed.
| Check | Expected for this fixture | What a mismatch suggests |
|---|---|---|
| Dimensions | 40 × 30 × 20 mm | Wrong units, extrusion distance or selected profile. |
| Volume | 24,000 mm³ | Missing material, multiple bodies or an unintended operation. |
| Surface area | 5,200 mm² | Unexpected geometry even if the silhouette looks plausible. |
| Round trip | Same dimensions after reopening the export | An export/import or unit interpretation problem. |
Next, change only the extrusion distance to 25 in a copy of the script and generate a separate export. The expected volume becomes 30,000 mm³ and area 5,900 mm². Keep both files and their measurement records. Add holes or fillets only after this baseline works; every extra feature introduces another reason for a mismatch.
Make the agent inspect its own edits
The v0.20.0 MCP guide distinguishes a headless design session from a bridge to a running desktop app. In headless mode, solidcraft-cli mcp owns its own design. The --connect option drives an app launched with its control interface. Pick the session deliberately so that an agent does not edit a different design from the one you are reviewing.
Use list_commands and describe_command to discover the available operation and its arguments. inspect_design reports the timeline and bodies, while measure reports geometric quantities. Ask for the measurement result after each meaningful change. A screenshot helps inspect appearance, but cannot replace a volume or dimension check.
For a short multi-step change, batch defaults to rollback on failure. The documented checkpoint restores the design and undo history; batches that create or open a document have a separate file-path caveat. Keep file export outside the geometry-edit batch and verify it separately. Do not treat a successful design rollback as proof that every external artifact was restored.
After a bridge connection drops during a mutation, inspect the design before repeating it: the operation may already have run. For a timeout, the running tool can identify active or queued app requests. In your own controller, retain the intended edit and observed result together instead of deciding to retry from a missing reply alone.
Keep test designs and exports in a dedicated project directory. The MCP guide documents scoped file access and explicit allow-path directories. Limit the working area to the files required for the part, then save a new revision before exploring a risky feature combination.
Use CAD views as references, and keep geometry authoritative
After the fixture passes, produce a clean view of the real part and retain its CAD revision, camera and dimensions. Decide whether the deliverable is an engineering file or a marketing image. A generated studio scene can support the latter, but it does not provide a new editable CAD model or certify a manufacturing tolerance.
SJolt’s Nano Banana 2.1 image-edit route accepts a prompt and one to fourteen public PNG, JPEG or WebP reference image URLs. Its documented controls include aspect_ratio and resolution. Export an image first: a STEP file or a .solidcraft design is not a valid image reference for that route.
An original presentation brief could request a neutral studio background while preserving the enclosure’s silhouette, openings and visible fasteners. Review those details against the CAD view at matching scale. Reject a beautiful result if it invents a port, fills a vent or changes the wall outline. Generated pixels remain a presentation asset even after that visual review.
Store the measured CAD revision, reference raster, generation task ID and accepted image together. Let geometry changes start a new CAD revision, then regenerate the reference deliberately. No SolidCraft connector, CAD conversion service, engineering certification or paid image result is claimed by this workflow.
Sources & further reading
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