Importing CAD and 3D files

Use Open CAD file... from the home lobby or the Project menu to start a new project from an existing file. It opens your system file picker directly. Prompt2CAD supports DWG, DXF, SketchUp (.skp), OBJ, STL, GLB, and self-contained glTF files up to 50 MB, 2,000,000 triangles, or 500,000 drawing-reference segments.

An opened model becomes a normal Prompt2CAD project, not a read-only viewer. Continue designing it with the agent: inspect dimensions, modify parts, add parametric features, replace components, combine source and generated geometry, and export the completed design. See the CAD file import overview for examples.

You can also attach up to four supported CAD/3D files beside the Direct prompt before starting a project. An attached file is associated with the project and shown as a file badge in chat, but it is deliberately not added to the 3D viewport. The agent can inspect its parts, dimensions, layers, and profiles, then use those facts as reference while building new parametric geometry. It only places the source geometry in the viewport when that is necessary for the request.

Open a shared file link

To open a CAD file hosted elsewhere, share a direct-file link in this form:

https://prompt2cad.com/import-cad?url=https%3A%2F%2Fexample.com%2Fbracket.dxf

The linked address must point directly to one supported CAD file and allow browser access (CORS). Links to a sign-in page, a sharing preview, or a host that blocks browser downloads will not open. The file is downloaded directly to the browser and still has the same 50 MB limit.

Opening and parsing a file consumes no credits. Sign-in is required to create the project, and agent requests after import use the normal chat-credit flow.

What opens in the viewport

The file appears in the 3D viewport immediately. You do not need to ask the agent to convert it first.

This immediate behavior applies to Open CAD file.... Files attached to a direct prompt remain inert until the agent explicitly uses one. Inspecting an attachment never changes the viewport.

• OBJ, STL, GLB, glTF, SketchUp, and 3D DXF/DWG faces open as persistent project parts. Separate, unconnected solids within one source mesh are split into individually selectable parts. The agent can preserve source geometry, apply local operations, replace components with parametric construction, or add scoped geometry without changing unaffected siblings.
• Closed 2D DXF polylines and circles open as parametric extruded plates. Choose their thickness in the import dialog; contained outlines become cut-through holes automatically. DWG keeps these as 2D linework instead, because it is commonly used for floor plans.
• Open 2D linework such as floor-plan walls, doors, furniture outlines, and arcs opens as zero-thickness reference lines grouped by layer. DWG also keeps closed planar shapes as reference lines. These references are visible in the viewport but are not physical parts, do not receive shadows, and are not included in solid-model exports.
• A GLB's simple source colors are preserved where possible. Other imports use a neutral material until you or the agent changes it.
• Imports retain up to 5,000 physical parts as separate selections across every supported format. If a file exceeds that safety limit, remaining mesh geometry is grouped into one overflow part.
• SketchUp files also keep source part names, so you can select a specific named part before asking for a change. Original SketchUp textures are not imported.
• When nested or overlapping parts sit under the same point, click that point again to cycle from the outer part to the parts behind it. The selection breadcrumb shows the retained source hierarchy.
• DWG files are converted in your browser before opening. Prompt2CAD reads the same practical geometry it supports from DXF files; use DXF when you need to send your finished design back to a CAD application, because native DWG export is not available.

Choose the source units in the import dialog. Prompt2CAD guesses units, but a millimeter-versus-meter mismatch makes the model 1,000 times too large or small.

Working with the agent

The agent works with an imported project like any other design. Source-aware tools let it inspect the original structure while it performs normal modeling operations:

• Ask it to inspect the import when you need a part list, exact dimensions, layers, triangle counts, or the original points of a 2D profile.
• For a direct-prompt attachment, say whether it should be used only as reference (for example, "inspect this bracket and build a matching mount") or placed in the result ("include the attached bracket in the assembly"). If you do not ask to place it, the source stays out of the viewport and exports.
• Ask it to change an imported DXF profile and it can edit the generated extrusion code directly. It can also regenerate selected profiles at a different thickness when that is the right operation.
• Ask for the change you need, for example: "add a mounting hole to this bracket," "make this leg 40 mm shorter," or "attach a handle to the inside drawer." The agent targets the affected parts and leaves the rest of the model intact. In GLB and SketchUp files, source hierarchy helps it distinguish nested parts precisely.
• Build forward from the import: add matching mounts, panels, fixtures, enclosures, or furniture; replace a component; or assemble new parametric geometry around supplied hardware.

Prompt2CAD preserves source geometry where that retains the most fidelity and changes the parts your request targets. Depending on the operation, a part can remain in its source representation, receive local geometry operations, or be rebuilt with parametric construction. These are implementation choices inside one project workflow, not separate classes of editable and non-editable content. You can reset a changed part to its source geometry later.

DXF scope

DXF support is intended for practical geometry, not the entire DXF specification:

• Reusable blocks and their placed copies are expanded into the positioned geometry you see, including nested blocks, rotation, and scaling. DWG files are converted to DXF in the browser before import.

• Model-space geometry on visible layers is imported. Paper-space entities and layers marked off or frozen in the source drawing are omitted.

• Supported: 3DFACE meshes; open LINE, LWPOLYLINE / POLYLINE, and ARC linework; closed LWPOLYLINE / POLYLINE outlines (including bulge arcs); and circles.

• Not imported: text, dimensions, and other annotation entities. The agent can inspect and report skipped entity types.

For a 2D laser-cut or panel drawing, use closed outlines. For a 3D DXF, export faces (3DFACE) from the originating CAD tool.

Storage and sharing

Imported mesh data and the parsed contents of passive CAD/3D attachments are stored locally in this browser and included when you download a .p2cad project file, so that archive can be opened on another device with its project files still inspectable.

For signed-in projects, original CAD sources and direct-prompt attachments up to 10 MiB each are backed up privately with the project. Opening that project on another signed-in device restores and parses the original sources automatically. Sources above 10 MiB remain local-only; export a .p2cad project file or attach the source again on the other device. The lightweight attachment record and generated parametric geometry sync in either case.

Not supported yet

STEP, IGES, native SolidWorks/Fusion files, and generic .gltf files with external .bin buffers are not supported. Export a self-contained GLB, OBJ, STL, SketchUp, or compatible DXF first.

Next: Exporting overview — take the updated model back to other CAD tools.