3D model from a drawing in KOMPAS: how to build and check it
Short answer: A 3D model from a drawing is built in KOMPAS-3D like this: the main sketch with dimensions from the drawing → a “Revolve” or “Extrude” feature → cuts and holes → chamfers and fillets → a dimension check and saving to STEP. Building is usually not hard — what takes longest is getting the datums and counts right and checking the model. If you have many drawings, scans, or need the model today, ordering is cheaper: you see the model and the check of every dimension for free.
Build order from a drawing
- Read the whole drawing. Main view, sections, details, notes and technical requirements. Mark the datums — what the dimensions are measured from.
- Choose the main sketch. A turned part (shaft, bushing, flange) — a profile on a plane and a “Revolve” feature. A housing or plate — an outline and an “Extrude” feature.
- Dimensions — only as numbers from the drawing. Don’t trace the picture: the scale of a scan or PDF is off. Tie dimensions to the same datums as on the drawing.
- Features — in manufacturing order. Main body → cuts and slots → holes with the “Hole” command (with threads) → chamfers and fillets at the very end.
- Repeats — as patterns. “4 holes”, “6X” — a rectangular or circular pattern, not six separate holes: simpler and fewer mistakes.
- Check the model. Measure 5–10 key dimensions with the measuring tool, and compare the mass (mass properties) with the one on the drawing, if given.
- Save it for the shop. For another CAD and the CNC programmer — STEP (AP214 or AP242); for 3D printing — STL; the drawing — from the model with the create-drawing command.
Where people go wrong most often
| Mistake | What it looks like | How to avoid it |
|---|---|---|
| A dimension from a different datum | The hole is where the picture shows it, but shifted by 2–6 mm | Before sketching, find on the drawing which line the dimension starts from; one datum for all dimensions of a group |
| “2X”, “4 holes”, “6×45°” | One hole or one chamfer made instead of several | Read the count at every dimension; repeats — as a pattern |
| A dimension on another view | The slot depth was taken from the main view, but the section shows a different one | Check every feature on all views where it appears |
| The closing link of a dimension chain | The sum of the links doesn’t equal the overall length, the model “doesn’t close” | Build from the overall dimensions; the closing link is for checking |
| An inch drawing | The model is 25.4 times smaller, or values rounded “by eye” | Convert every dimension: 1 inch = 25.4 mm, without rounding to tenths |
The catch is that a model with such a mistake looks right. Only measuring finds it — that is why we measure every drawing dimension on the finished model with software, and a second checker re-reads the sheet from scratch.
Check the model before sending it to the shop
Tick what you have already checked
PDF and scans in KOMPAS
KOMPAS itself does not open a PDF as a drawing: according to the v23 help, PDF is export-only, while DXF, DWG and IGES can be imported. A vector PDF exported from CAD is converted to DXF — the lines survive, but dimensions remain lines and text, and there is no model. A scan or photo can be inserted into a sketch as a background and traced, but still take dimensions as numbers — the scan’s scale is inaccurate.
Do it yourself or order it
| Yourself in KOMPAS | Freelancer | RODEx | |
|---|---|---|---|
| Price | Your time | RUB 500–3500, 1–4 days | $8–$25, shown before payment |
| Turnaround | Depends on experience and the part | 1–4 days | Usually 20–30 minutes |
| Dimension check | Yourself | As the freelancer does it | Every dimension measured on the model, a check table |
| Feature tree in KOMPAS | Yes | If they work in KOMPAS | No: the STEP is a finished solid that KOMPAS opens |
| When to choose | You are learning, the part is simple, you need a parametric model | You need a model in your CAD with a feature tree | Many drawings, scans, an archive, needed today |
A model from your drawing — today
Questions and answers
How to make a 3D model from a drawing in KOMPAS?
Build the main sketch with dimensions from the drawing, make the body with a “Revolve” or “Extrude” feature, add cuts and holes, and chamfers and fillets at the end. Then measure the key dimensions and save the model as STEP.
Can I insert a picture of the drawing into KOMPAS and trace it?
You can insert a scan into a sketch as a background, but take dimensions only as numbers from the drawing: the scale of a scan or PDF is inaccurate, and a model traced “from the picture” will not match the drawing.
How to open a PDF drawing in KOMPAS?
Not directly: in KOMPAS-3D v23 PDF is export-only. A vector PDF is converted to DXF with a converter and the DXF is opened; dimensions then remain plain lines and text.
Will the ordered model have a feature tree?
No: we deliver a STEP — an exact solid that KOMPAS opens as a part. Dimensions can be changed by direct editing; if you need a model with a feature tree in KOMPAS specifically, that is a designer’s job in your CAD.
How much does it cost to order a 3D model from a drawing?
With us $8–$25 depending on complexity; you see the price before you pay. On Kwork a basic order is RUB 500–3500 for 1–4 days.