# How to make a desktop pencil divider with vibe CAD

Convert an existing desk cup into separate pencil compartments using a removable insert fitted to the cup rather than a generic cylindrical assumption.

Category: Desk. Difficulty: Beginner.

By partsforagents · AI-authored · Updated 2026-11-10.

## Make this project
This is an unprinted removable organizer for an existing cup. It is not a drinking-cup accessory or a food-contact design.

This recipe has not been physically validated. Create and inspect the exact CAD for your dimensions; a concept image is not an orderable CAD file.

## 1. Measure
- Measure the cup opening in two directions and its interior width at the intended insert depth.
- Record the usable internal height and any tapered walls or rounded bottom.
- Measure the thickest pencil, marker or eraser-ended tool assigned to each compartment.
- Select the number of compartments and a removable-fit gap using a cardboard mockup.

## 2. Give your CAD agent this prompt

Model a removable cup divider with opening_width, opening_depth, lower_width, lower_depth, insert_height, divider_count and perimeter_gap. Represent the cup taper explicitly and keep the bottom open. Ask for the cup cross section and largest tool diameters. Do not add a press fit or flexible retention tabs unless separately specified and sampled.

## 3. Model and inspect
1. **Describe the cup interior** — Sketch the opening and a lower cross section. Connect them with a tapered envelope that stops above any rounded base in the cup.

2. **Divide by actual tools** — Place divider walls inside that envelope using measured tool groups. Make one wider compartment where markers or erasers need more room than pencils.

3. **Provide a removal grip** — Add a small raised finger tab near the center. Round exposed upper edges and keep the tab away from the normal pencil-grabbing area.

## 4. Check the prototype
- Try a cardboard cross-shaped insert in the cup to confirm taper, depth and removal access without forcing it.
- Inspect the minimum compartment width at the bottom, where a tapered cup can pinch the thickest tool.
- Compare exported upper and lower dimensions with the cup measurements and request a perimeter-fit sample if uncertain.

## Avoid this mistake
Measuring only the cup mouth produces an insert that may jam lower down; model the interior taper and bottom radius.

## Choose the material
PLA or PETG may suit a desk insert concept. Choose wall thickness through a sample and do not assume either material makes a forced fit removable.

## Order this part now

[Submit your CAD](https://partsforagents.com/for-humans?project=desktop-pencil-divider#workspace) or [connect your agent](https://partsforagents.com/guides/cad-to-print#connect).

Have the model ready? Upload the exact customer-approved file. Starting from this guide? Generate the CAD from your measurements, inspect it and export the revision you want made. Include this guide URL in the review notes; the file and approved specification determine the part.

Required inputs:
- Authorized exact CAD file
- Declared units
- Material family and requested grade/color
- Quantity
- Intended use and critical fit requirements
- Contact email
- Destination country and postal code

**No payment at submission.** Submit a nonbinding manufacturing request now; the exact reviewed offer and payment link follow when ready. Current firm production scope is reviewed PLA/PETG for eligible contiguous-US/DC delivery.

### Agent submission steps
1. **upload_cad_request** — Get authorization to store/process the exact exported file, then use its bytes and approved intake fields. Save the returned request ID and file SHA-256.

2. **get_cad_preflight** — Read measured geometry and unknowns for that uploaded file.

3. **set_manufacturing_specification** — Save the customer-approved manufacturing choices and returned specification fingerprint.

4. **place_order** — Submit order_type manufacturing with the real request ID, exact specification fingerprint, acknowledge_nonbinding true and a saved unique idempotency key. Include this guide URL in review_notes along with the approved requirements.

5. **get_order_fulfillment** — Use the returned order ID to read the authoritative offer and manufacturing progress. A recipe URL alone never identifies an order.

Reconcile an uncertain result before retrying. Reuse identical arguments and the same idempotency key; never submit a second request just because its payment link is pending.

## Machine-readable resources

- [This complete guide as JSON](https://partsforagents.com/vibe-cad/desktop-pencil-divider/guide.json)
- [All project guides](https://partsforagents.com/vibe-cad/catalog.json)
- [Exact tool schemas](https://partsforagents.com/tools.json)
- Full workflow MCP: https://partsforagents.com/api/mcp (authenticated)
- Free advice MCP: https://partsforagents.com/api/advice/mcp
- Canonical guide: https://partsforagents.com/vibe-cad/desktop-pencil-divider