Outsourcing AutoCAD and SolidWorks Drafting: Files, Standards and What Drives the Price

Outsourcing technical drawing is one of the most practical ways to add capacity without growing the in-house team. But the quality of the result depends less on the drafter than on the information you give them. A vague sketch, an unclear dimension or an unstated standard is the most common reason revision rounds drag on.

This guide covers what to send when you commission AutoCAD or SolidWorks work, what each file format is for, how standards and tolerances come into it, and what shapes a quote.

2D or 3D: which do you need?

AutoCAD is mostly used for 2D: floor plans, MEP layouts, sections, elevations and fabrication drawings. SolidWorks is a parametric 3D solid modeller: parts, assemblies and the manufacturing drawings generated from them. If a product will be manufactured, you usually want the 3D model and the 2D manufacturing drawings derived from it. For building or site work, 2D plans and sections may be enough. Saying which one you need up front is what makes a quote accurate.

File formats: what each one is for

Format	What it is for
DWG	AutoCAD's native 2D/3D format. The standard for editable delivery.
DXF	An open, portable drawing format. Laser, plasma and CNC cutting machines usually ask for it.
PDF	For approval, print and archive. Not editable; also useful as a reference you send us.
SLDPRT / SLDASM	SolidWorks part and assembly files. They keep the feature tree so you can edit later.
STEP / IGES	Neutral formats for exchanging 3D geometry between CAD systems. STEP is the more common and more reliable choice today.

State your delivery formats at the start. If your manufacturer only accepts STEP, say so. If your own team will edit the model, ask explicitly for native SLDPRT/SLDASM and DWG files.

What to send the drafter

• Source material: old drawings, PDFs, hand sketches, photos and measurement notes. Include a scale reference object in photos.
• Dimensions: mark which dimensions are critical and which can be approximate.
• Material and process: sheet metal, machined, cast, welded fabrication. The process drives design decisions.
• Standard and units: millimetres or inches, first-angle or third-angle projection, ISO or your company standard.
• Title block and template: your logo, sheet layout and numbering convention, if you have them.
• Purpose: manufacturing, permit, quotation or documentation. Purpose sets the level of detail.

Standards, layers and tolerances

A drawing has to follow a standard to be useful. In general, ISO technical drawing conventions govern dimensioning, line weights and text height. If you have an internal standard, the fastest route is to share a model drawing that follows it.

In DWG files, layer structure matters to everyone who uses the file afterwards. Walls, dimensions, centrelines, text and hidden lines on separate layers make printing and editing much easier. If you have a layer naming convention, provide it up front.

Think of tolerances on two levels: general tolerances, usually a tolerance class noted on the drawing, and specific tolerances on critical features such as fits, bearing seats and mating surfaces. Talk to your manufacturer about what each process can realistically hold. Specifying tighter than needed raises cost; specifying looser than needed causes assembly problems.

Managing revision rounds

Put the scope in writing before the first delivery. Be clear on how many revision rounds are included and what counts as a revision versus new work. Fixing a drafting error is not the same as changing the design: if the drafter drew it wrongly, the correction does not use up your rounds; if you changed the design, that is new scope.

Give feedback in one numbered list. Marking up a PDF with clouds and notes is among the fastest methods. Use a revision letter or number in file names and archive older versions.

Confidentiality and NDAs

Product drawings often contain trade secrets, so signing a non-disclosure agreement before sharing files is routine. The NDA should cover scope, retention period and what happens to the files once the project ends, whether deletion or return. Share files through a controlled channel and know who has access. If you operate in the EU or UAE, check whether any personal data appears in the documents you send and handle it accordingly.

What drives the price

Quotes follow project scope more than a fixed rate card. The main factors:

• Number of parts or sheets and the complexity of the geometry.
• Quality of the source: redrawing from a scanned legacy drawing differs from designing from scratch.
• 2D or 3D, and whether assemblies and manufacturing drawings are needed.
• How tight the standard and tolerance requirements are.
• Number of revision rounds.
• Turnaround time and urgency.
• Custom templates, layer structure or special delivery formats.

Turnaround follows the same logic: the clearer your source, the fewer questions go back and forth and the more predictable delivery becomes.

Pre-send checklist

1. Is the purpose written down (manufacturing, permit, quotation)?
2. Are 2D/3D needs and delivery formats stated?
3. Are source files and photos scaled?
4. Are critical dimensions and tolerances marked?
5. Have you shared the standard, units and title block template?
6. Is revision scope and number of rounds agreed?
7. Is the NDA signed?

Common mistakes and how to avoid them

The first mistake is sending unscaled photos or scans and expecting the drafter to guess. A guessed dimension can become an expensive error in manufacturing; if a dimension is unknown, say so and decide it together. Second is leaving out units: mixing millimetres and inches is one of the oldest and costliest mistakes in the industry. Third is giving revisions through different channels such as phone, chat and email, which makes it hard to know which request is current. A single list and a single responsible person solve most of this.

Another frequent issue is missing manufacturing information on the drawing: surface finish, heat treatment, coating, weld symbols, sheet thickness and bend radii are often forgotten. Adding them at drafting stage saves your manufacturer from coming back with questions. If your supplier has their own drawing requirements, share that specification with the drafter as well.

In our process, automation speeds up drawing preparation and an expert in the discipline reviews and approves every delivery. To describe your project and get a quote based on scope, see our CAD drafting service or send us a message.