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

# CAD Analysis

> The CAD analysis workflow end to end — from upload and first question to targeted renders and turning findings into real ProDex BOMs.

## Overview

Analyzing a CAD file is a conversation, not a form to fill in. Under the hood, [Dexter](/product/ai-assistant) works through a consistent arc — *what is this file → what's written on it → what does it look like in 2D → what's its 3D structure → what's the answer to your question* — but you never have to name those steps. Ask in your own terms and Dexter reaches for the right operation.

Everything below assumes a file in a [supported format](/product/cad/supported-formats); the examples use a structural DWG assembly, the richest case. Formats aren't interchangeable, though: DWG and DXF carry layers, text labels, part marks, and 2D drawing views, while a STEP file brings assembly structure and placement counts but no layers, labels, or 2D drawing — so the layer-and-label parts of this walkthrough don't apply to STEP. 3D structure from a DWG also depends on the AutoCAD release — only AutoCAD 2018 (AC1032) DWGs go through the 3D path. Older releases still open for their 2D content (identity, layers, labels, and 2D renders), but the 3D path rejects them with a clear error that points you to re-export as DXF or STEP.

## Step 1 — Upload and Ask

Attach the CAD file to a chat with Dexter, then ask an open-ended first question:

* *"I've attached a structural assembly drawing — can you tell me what it is and give me a BOM?"*
* *"What's in this DWG?"*
* *"Analyze the attached file."*

<Tip>
  **One open-ended prompt is enough.** You don't need to request identity, labels, and renders separately — a single "what is this?" gets you the combined first read below. A narrower question gets a narrower answer: Dexter goes as deep as your prompt asks and stops once it's answered, so ask broadly when you want the full picture. Either way, nothing runs on upload alone; analysis starts with your first question.
</Tip>

## Step 2 — The First Pass

Dexter's first reply is a combined read of the whole file, in this order:

1. **Identity** — format and version (e.g. "AutoCAD 2018 / AC1032"), overall extents, and units. For DWG, units come with an explicit caveat: the format has no unit header, so they are inferred from geometry.
2. **Layers and entities** — the layer list grouped into inferred sub-assemblies, plus a tally of entity types.
3. **A synthesized BOM** — a table of unique part marks grouped by sub-assembly, with solid-body counts per assembly. Labels recovered from corrupted text are called out individually.
4. **A 2D overview render** — a full-page image of the drawing, inline in the chat.
5. **A short synthesis** — a plain-language readout, e.g. *"a structural panel unit: 9 part marks across 4 sub-assemblies, plate gauges 3/16″, 1/4″, and 5/8″."*

<Note>
  **Findings are traceable.** Every number in the reply is tied back to the specific analysis step that produced it, so you can always ask Dexter where a figure came from and how it was derived.
</Note>

## Step 3 — Drill In

From the first pass, follow your questions wherever they go. Each ask maps to a concrete operation:

| You ask                                                             | You get                                                                                |
| ------------------------------------------------------------------- | -------------------------------------------------------------------------------------- |
| "Show me part mark B-204 up close"                                  | A targeted 2D crop framed on that part mark                                            |
| "Zoom in on the STRUCTURAL layer"                                   | A layer-scoped 2D crop                                                                 |
| "Render just this region"                                           | A crop of the bounding box you describe                                                |
| "Give me an isometric 3D view"                                      | A 3D render with a color legend per sub-assembly                                       |
| "Top view" / "front" / "side" / "bow" / "under"                     | The corresponding named 3D view                                                        |
| "Rotate it — 30° azimuth, 20° elevation"                            | A custom-angle 3D render                                                               |
| "Spin it — show me several angles"                                  | A series of orbiting 3D views                                                          |
| "What are the plate thicknesses?" / "How big is sub-assembly B?"    | 3D mesh statistics: plate gauges, per-assembly dimensions, sample plate sizes          |
| "What text is on the drawing?" / "Find every label containing STRL" | The full text-label list with positions, optionally pattern-filtered                   |
| "Are there curved features I might be missing?"                     | The count of curved faces excluded from the 3D mesh, stated plainly                    |
| "Turn this into a report"                                           | A hand-off to [reports](/product/dexter/reports) for a PDF, deck, or Excel deliverable |

The named 3D views are fixed — **iso, top, front, side, bow, under** — with custom azimuth/elevation and spin covering every other angle.

## Getting Geometry Out

CAD analysis is read-and-render only. Dexter reads the full solid geometry and renders it inline, but it does not produce exported CAD geometry files — a DXF, or an STL/OBJ/GLB/PLY mesh — that you can download or open in another tool. What you take away from a session are the findings, tables, and rendered images in the chat; to keep those as a shareable artifact, ask Dexter for a [report](/product/dexter/reports), which captures the findings and renders (not a re-export of the source geometry).

## Working with Multiple Files

You can attach several CAD files to one conversation and ask across them:

* *"Compare the plate-gauge distribution between unit-A.dwg and unit-B.dwg."*
* *"Do these two STEP assemblies share any component names?"*
* *"Which of these three files has the most sub-assemblies?"*

Each file is analyzed independently; the comparison is a synthesis Dexter builds across the per-file results, presented as prose and tables. There is no built-in CAD diff, side-by-side viewer, or automatic cross-file BOM reconciliation.

<Info>
  Comparisons across **mixed formats** are apples-to-oranges in places: the DWG side brings layers, part-mark labels, and planar-only 3D, while the STEP side brings product structure, placement counts, and complete 3D. Same-format comparisons are much cleaner.
</Info>

## From CAD Findings to a Real BOM

The BOM in the chat is a finding, not a record — a structured reading of the file, not a [BOM](/product/bom-overview) object in your factory. There is no one-click "promote to BOM" button; instead, you ask Dexter to *author* a real BOM using the analysis as its input. Ask explicitly:

* *"Turn this into a ProDex BOM I can use in planning."*
* *"Create entities for these parts and build a BOM."*

Dexter then builds the BOM by hand from the findings, with you approving each step:

1. **Proposes an entity per unique part mark** (or per STEP component), using the part mark as the identifier and carrying over dimensions and gauges from the analysis.
2. **Presents the list for your review before creating anything.** This is where you confirm units (especially for DWG, where they were inferred), part-mark spellings, whether any recovered-from-corruption marks are real, and whether STEP placement counts truly equal physical quantities.
3. **On your approval, creates the entities and the BOM**, with line quantities taken from solid-body counts (DWG/DXF) or placement counts (STEP). Sub-assemblies in the CAD file typically become nested BOMs, so the structure survives.

Caveats to keep in mind:

* **Quantities are structural, not authoritative.** Body counts and placement counts are the best proxies the file offers, but reconcile against your engineering BOM if one exists.
* **Materials, finishes, tolerances, and vendor data are not in the CAD analysis** — add them to the entities and BOMs afterward.
* **The flow is one-way.** Editing the CAD file later does not re-sync the BOM; a re-import is a fresh analysis plus a manual reconciliation.

## 2D-Only Drawings

A DWG or DXF without 3D solids is still very usable:

* **Works fully**: identity, the layer list, every text label (including pattern search and corrupted-label recovery), 2D overview and crop renders, and the label-based BOM.
* **Degrades**: per-assembly solid-body counts are unavailable (there are no solids to count), so the cross-check that normally catches part-mark undercounts isn't available.
* **Stops cleanly**: 3D operations report that the file has no meshable solids — a clear signal, not an error — and Dexter skips 3D renders and mesh statistics.

## Boundaries

* **Chat is the only trigger.** There is no user-launched "Analyze CAD" [workflow](/product/dexter/custom-workflows), no CAD step in [pipelines](/product/templates), and no scheduled or watch-folder re-analysis. Projects can contain CAD-driven work, but the analysis itself always happens in chat turns.
* **Nothing persists between sessions.** Every analysis re-reads the file; ask Dexter to capture important findings in [memories](/product/dexter/memories), a report, or real BOMs if you'll need them again.