---
title: "Attach an uploaded CAD model and render its thumbnail"
method: POST
path: "/cell_specifications/{cell_spec_id}/cad/confirm-upload"
tags: ["Cell Specifications"]
---

# Attach an uploaded CAD model and render its thumbnail

`POST /cell_specifications/{cell_spec_id}/cad/confirm-upload`

## Request

- Base URL: `https://api.ionworks.com`
- URL: `https://api.ionworks.com/cell_specifications/{cell_spec_id}/cad/confirm-upload`
- Auth: none declared

Attach the uploaded model to the spec, replacing any previous one.

Renders a PNG thumbnail of the model. A model that cannot be rendered is
still attached, with ``thumbnail_url`` null and the reason in
``thumbnail_error``.

## Path parameters

- `cell_spec_id` string, uuid, required

## Request body

- CadConfirmRequest: Identifies the upload being confirmed.
  - `file_name` string, required: Filename of the model, e.g. 'cell.step'. Its extension selects the format: .step, .stp, .iges, .igs, .stl, .obj, .ply, .glb, or .off.
  - `upload_id` string, required: The upload_id returned by initiate-upload.

## Response `200`

Successful Response

- CellSpecificationCad: A cell specification's CAD model, with short-lived URLs to fetch it.
  - `file_name` string, required: Original filename of the model.
  - `download_url` string, required: Signed URL to download the model.
  - `thumbnail_url` string, nullable: Signed URL of the rendered PNG thumbnail; None when the model could not be rendered.
  - `thumbnail_error` string, nullable: Why rendering failed, when it was just attempted and did. Only set on the confirm-upload response.

## Other responses

- `422`: Validation Error

## Changes

- **2026-10-04** `1f50d4b61910`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/ionworks/apis/ionworks-api/changes/cell_specifications/:cell_spec_id/cad/confirm-upload/post.md)

---

[API](https://skmtc.dev/ionworks/apis/ionworks-api.md) - [All operations](https://skmtc.dev/ionworks/apis/ionworks-api/llms.txt) - [OpenAPI document](https://skmtc.dev/ionworks/apis/ionworks-api/revisions/abebbbc5f60a?raw)