> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cosmon.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CAD Modeling

> Build, modify, and parameterise geometry in your CAD tool using natural language.

## Overview

Nexus can create and modify geometry directly in SolidWorks — sketches, features, surfaces, and assemblies. You describe the shape and intent; Nexus handles the feature tree.

This is useful when creating geometry from a specification, making systematic edits across many features, re-parameterising existing models, or applying changes that are tedious to perform manually.

## What Nexus can help with

* **Part modelling** — Create bosses, cuts, fillets, ribs, shells, sweeps, lofts, and complex surfaces from a written description.
* **Parametric editing** — Change dimensions and relationships across an entire feature tree without opening each feature individually.
* **Assembly management** — Add, suppress, or reorder components; create and update mates; run interference checks.
* **Configuration and variants** — Generate a family of parts (small, medium, large) from a master model, or create a simplified body for simulation.
* **Import and repair** — Import STEP/IGES files and repair common translation issues (missing faces, open bodies, duplicate geometry).
* **File export** — Export the active part or assembly to a neutral or downstream format (STEP, IGES, Parasolid, STL, DXF, PDF) with the right options for the destination — tessellation quality for STL, simplified vs. as-modeled geometry, units, and configuration selection.

## Example prompts

<AccordionGroup>
  <Accordion icon="cube" title="Create a part from a description">
    ```text theme={null}
    Create a new part: a rectangular base plate 120mm x 80mm x 6mm. Add four M6 counterbored holes at each corner, 10mm from each edge. Add a 2mm fillet on all top edges. Set the material to Aluminium 6061-T6.
    ```
  </Accordion>

  <Accordion icon="pen-ruler" title="Parametric edit across files">
    ```text theme={null}
    In C:/Projects/Bracket/bracket_v3.SLDPRT, change the boss diameter from 20mm to 25mm. Then update the clearance hole in the mating part at C:/Projects/Bracket/clearance_plate.SLDPRT to match, with 0.5mm clearance.
    ```
  </Accordion>

  <Accordion icon="layer-group" title="Assembly operation">
    ```text theme={null}
    Open C:/Projects/Pump/pump_asm_v2.SLDASM. Suppress all fasteners (screws, bolts, washers, nuts) and hide the housing body. Take a screenshot of the exposed internal components.
    ```
  </Accordion>

  <Accordion icon="copy" title="Create a part family">
    ```text theme={null}
    From the current master part, create three configurations named Small (scale factor 0.8), Standard (as-is), and Large (scale factor 1.25). Save each as a separate SLDPRT file in C:/Projects/Family/.
    ```
  </Accordion>

  <Accordion icon="wrench" title="Import and repair">
    ```text theme={null}
    Import C:/Incoming/housing_supplier.step and check it for translation issues. Report any open bodies, missing faces, or duplicate geometry. Attempt automatic healing and confirm the resulting body is solid.
    ```
  </Accordion>

  <Accordion icon="file-export" title="Export to a neutral format">
    ```text theme={null}
    Export the active assembly to STEP AP242, units millimetres, as-modeled geometry (not simplified). Also export a lightweight STL at 0.05mm tessellation tolerance for a 3D print check. Save both to C:/Projects/Pump/export/ using the assembly file name.
    ```
  </Accordion>
</AccordionGroup>

## Tips for geometry prompts

* **Reference features by name** — "The Base-Extrude feature" or "the M8 tapped hole pattern" is more reliable than "the first boss" when editing existing models.
* **Specify the plane** — For sketches, say "on the top face" or "on the Front plane" to avoid ambiguity.
* **Use relative positioning** — "10mm from the edge", "centred on the face", "offset 5mm from Datum Plane 1" — Nexus understands spatial language.
* **State current state** — If modifying an existing part, briefly describe the relevant current state if it's not obvious from the file name or context.
* **Name the destination format's requirements** — exporting for a supplier, a simulation, or a 3D print each call for different settings (as-modeled vs. simplified geometry, tessellation tolerance, units). State what the export is for so Nexus picks sensible defaults.