<assembly.part />

assembly.part is a generic component of an assembly, such as a bracket, cover, or purchased mechanical part. Give it a stable name and optionally supply a CAD model. It has no PCB footprint, schematic symbol, or electrical ports.

import { assembly } from "@tscircuit/core"

export default () => (
  <assembly.device name="product">
    <board width="40mm" height="30mm" thickness="1.6mm" />
    <assembly.part
      name="bracket"
      displayName="Mounting bracket"
      cadModel={{
        glbUrl: "https://docs.tscircuit.com/models/assembly/bracket.glb",
        positionOffset: { x: 10, y: 0, z: 0.8 },
        rotationOffset: { x: 0, y: 0, z: 90 },
      }}
    />
  </assembly.device>
)

Part properties

Property	Description
name	Required stable identity. Trimmed and must not be empty.
displayName	Optional human-facing name.
model	Modelprinter/footprinter specification or an HTTP(S) model URL.
modelUrl	Imported model URL or asset path.
cadModel	Existing CAD formats and transforms, including CAD JSX; see cadmodel.
children	Child reference surfaces and nested assembly elements.

Supply at most one of model, modelUrl, or cadModel. Omit all three for a part with no geometry. cadModel={null} also keeps the part's identity without rendering a model; it cannot be combined with another model source.

Placement

Standalone parts use the world origin. Nested parts inherit the nearest assembly's placement. cadModel.positionOffset moves the model in that local frame; rotationOffset rotates it. A model's offsets do not move the assembly origin used by other elements.

Coordinates are in millimetres in a right-handed frame: +X right, +Y top, and +Z above the board. In the example, the top of the 1.6 mm board is at Z = 0.8 mm. These model transforms do not attach the bracket to mounting holes or create fasteners.

An assembly.screen can target the part's identity with connectsTo=".bracket". This uses the part's assembly origin, not the model's offset, and does not create electrical connections. pcbDisabled suppresses part CAD geometry.

Use assembly.printedpart for printable JSCAD geometry with named mounting faces, or assembly.subassembly to group nested assembly elements. A generic part has no mountedTo, mountFace, or jscad prop.

Define a mounting anchor

Add an assembly.referencesurface as a direct child to define a mounting frame independently of the CAD model. The default surface name is anchor, so other parts can target BRACKET.anchor. Its local center offsets measure from the part origin; model offsets do not move it.

This also works on a part with no model. See the reference-surface page's runnable lamp example for a base anchoring a printed stem and shade.