Generating Manufacturing Drawings in Inventor: Annotations, Dimensions, and GD&T

A 3D model is not a manufacturing instruction. The machinist cutting a part on a lathe or milling machine needs to know the tolerances on each dimension, the required surface finish, the datum scheme that establishes the part’s reference frame, and any geometric tolerances that govern the relationships between features. All of that information lives in the manufacturing drawing — the formal engineering document that bridges the gap between design intent and the workshop floor. Inventor’s drawing environment, built around the IDW (Inventor Drawing) format, provides the full suite of tools needed to produce manufacturing drawings that meet current technical standards.

This guide covers how to create professional manufacturing drawings in Inventor: setting up drawing views, applying dimensions and tolerances, adding GD&T (Geometric Dimensioning and Tolerancing) annotations, specifying surface finish, and managing drawing templates and title blocks.

Autodesk Inventor Professional is available from GetRenewedTech at £39.99.

Setting Up the Drawing Environment

Inventor drawing files (IDW) are separate from part and assembly files but maintain a live, parametric link to the 3D model. When you change a part dimension, the drawing automatically updates — views reproject, dimension values change, and section views redraw. This live link eliminates the most common source of drawing errors: a changed dimension that wasn’t updated in the drawing.

Drawing Templates

Before creating drawings, establish a drawing template that encodes your organisation’s standards. A good template includes:

• Sheet size and border (A0, A1, A2, A3, A4 to BS ISO 5457)
• Title block with fields for part number, revision, drawn by, checked by, date, tolerances, material, and surface treatment
• Default projection angle (first angle projection is standard in the UK; third angle is used in the USA)
• Default dimension style (dimension line, arrow head size, text height, precision)
• Standard notes (e.g., “Unless otherwise stated, tolerances are ±0.1mm linear, ±0.5° angular”)
• Your organisation’s logo in the title block

Create the template once, save it to a shared library location, and configure Inventor’s Application Options > File > Templates folder to point to it. All engineers in the team will then start from the same baseline, producing consistent drawings without manual reformatting.

Creating Drawing Views

Inventor’s Place Views tab provides all the view types needed for engineering drawings.

Base Views and Projected Views

Start by placing a Base View — the primary view from which all others are derived. For most parts, this is the front elevation, chosen to show the part’s primary profile. Set the scale (1:1, 1:2, 1:5, 2:1, etc.) and the view orientation. Once placed, use Projected View to derive the remaining orthographic views (plan, side elevations) by dragging horizontally or vertically from the base view. Inventor automatically maintains first or third angle alignment based on your template setting.

Section Views

Section views cut through the part to reveal internal features that would otherwise require many hidden detail lines. In Inventor, place a section line on an existing view using the Section View tool and drag out the resulting section view. Offset sections (where the cut plane steps to capture multiple features) and aligned sections (where the cut rotates to capture angular features) are both supported.

For threaded holes, counterbores, and other internal features, section views are essential for clear dimensioning. A common convention is to section through the centre of a bolt hole circle to show all holes in a single view without needing individual detail views for each.

Detail Views

Detail views magnify a portion of an existing view at a larger scale. Use them for small features — fine threads, small radii, delicate geometric relationships — where the main view scale is too small for clear annotation. A typical detail view circle the area of interest on the parent view and presents it at 2:1 or 5:1, with the detail label referencing back to the parent view.

Auxiliary Views

Auxiliary views project perpendicular to an inclined face, showing its true shape rather than the foreshortened appearance visible in standard orthographic views. For parts with angled features — machined tapers, inclined boss faces, angular flanges — an auxiliary view is often the only practical way to dimension those surfaces correctly.

Dimensioning the Drawing

Dimensions in Inventor drawings are placed using the Annotate tab. All dimensions are associative — they reference the actual model geometry, so if the model changes, the dimension value updates automatically.

Linear and Angular Dimensions

The General Dimension tool is the primary dimensioning tool. Click on a line or point and drag to place the dimension. Inventor intelligently detects whether you’re dimensioning a linear distance, diameter, radius, or angle based on what you’ve selected. Right-clicking a placed dimension allows you to set tolerances, change precision, add inspection flags, or switch between nominal and reference (REF) status.

Baseline and Ordinate Dimensioning

For parts with many features dimensioned from a common datum surface — CNC-machined plates with multiple holes and slots, for example — baseline dimensioning (also called chain dimensioning from a common origin) or ordinate dimensioning is more readable and less prone to cumulative tolerance errors than chain dimensioning. Inventor’s Baseline Dimension Set and Ordinate Dimension Set tools handle these efficiently.

Tolerances

Every dimension on a manufacturing drawing carries a tolerance, whether stated explicitly or implied by a general tolerance note. Inventor supports several tolerance annotation methods:

General Tolerances

Applied via the title block general tolerance note. In the UK, ISO 2768 is the common reference: ISO 2768-m (medium) specifies linear tolerances of ±0.1mm for dimensions up to 30mm, ±0.2mm for 30–120mm, ±0.3mm for 120–400mm, and so on. Most general machined features can be manufactured to ISO 2768-m without premium machining cost.

Explicit Tolerances

Functional dimensions — those that affect fit, function, or assembly — require explicit tolerances stated directly on the dimension. In Inventor, right-click a dimension, select Edit, and the dimension properties dialogue allows you to enter upper and lower deviations (e.g., +0.025/−0.000 for an H7 bore), symmetrical tolerance (±0.05), or select from standard fit designations.

Fit Designations

For mating dimensions (shafts and holes that must fit together), it is more informative to specify the ISO fit designation than individual tolerances. A 25H7/g6 fit (a clearance fit for a rotating shaft in a bearing housing, for example) communicates both the tolerance values and the engineering intent. Inventor allows you to specify fit designations that resolve to the correct tolerance values automatically based on the nominal dimension size.

Geometric Dimensioning and Tolerancing (GD&T)

GD&T is the formal system for specifying allowable variations in the form, orientation, location, and run-out of geometric features. It is defined by ISO 1101 (and the American ASME Y14.5 standard) and is essential for precision engineering where functional requirements go beyond simple size tolerances.

Why GD&T Matters

Consider a simple flanged coupling. A size tolerance on the bolt hole diameter tells the machinist how big each hole should be. But it says nothing about whether the holes are in the right positions relative to each other or relative to the bore centreline. Without positional GD&T, a part could have all holes within diameter tolerance yet be completely non-interchangeable because the hole circle is offset or uneven. GD&T closes this gap by specifying the allowable variation in position, perpendicularity, flatness, and other geometric characteristics.

GD&T Symbols in Inventor

Inventor’s Feature Control Frame tool places GD&T annotations following ISO 1101 or ASME Y14.5 conventions (selectable in the drawing standard settings). The full symbol set is available:

• Form tolerances: Flatness ⏥, straightness ―, circularity ○, cylindricity ⌭
• Orientation tolerances: Parallelism ∥, perpendicularity ⊥, angularity ∠
• Location tolerances: Position ⊕, concentricity ◎, symmetry ≡
• Run-out tolerances: Circular run-out ↗, total run-out ⇗
• Profile tolerances: Line profile ⌒, surface profile ⌓

Each feature control frame references a datum or datum system. Datums are defined by datum feature symbols (a filled triangle with a letter identifier) placed on the surfaces that establish the part’s reference frame. A well-structured datum scheme mirrors how the part will be fixtured for inspection, ensuring that the manufacturer and inspector are measuring from the same reference points.

Practical GD&T Applications

Common GD&T applications in Inventor manufacturing drawings include:

• Flatness on a machined sealing face: Ensures the face is flat enough to seal without gasket distortion. Typical values for precision engineering: 0.01–0.05mm.
• Perpendicularity of a bore to its face: Critical for press-fit bearing housings where a cocked bearing will cause premature failure.
• True position of bolt holes: Ensures interchangeability with mating flanges. A position tolerance of ⊕ Ø0.1mm means each hole centre must lie within a 0.1mm diameter cylinder centred on the true position.
• Run-out on rotating components: Limits the eccentricity of a shaft or bearing seat as the part rotates about its datum axis.

Surface Finish Specification

Surface finish symbols on manufacturing drawings specify the maximum allowable surface roughness of machined surfaces. Inventor supports ISO 1302 surface finish symbols, which specify the Ra (arithmetical mean roughness) value in micrometres. The symbol is placed on the surface in the view where it is visible, with the Ra value inside the symbol.

Common Ra values and their typical applications:

• Ra 6.3 μm: General machined finish — typical for milled or turned surfaces that don’t mate with other parts
• Ra 3.2 μm: Standard finish for mating surfaces, bearing seats, and gear flanks in low-speed applications
• Ra 1.6 μm: Ground finish for bearing housings, precision bore surfaces, sealing faces
• Ra 0.8 μm: Fine ground or honed — hydraulic cylinder bores, precision slideways
• Ra 0.4 μm and finer: Superfinished for high-speed bearing journals, optical components, fluid control valves

Parts Lists and Balloon Annotations

For assembly drawings, Inventor generates a Parts List table directly from the assembly BOM. Place the parts list on the drawing sheet and then use the Balloon tool to add numbered callouts referencing each component in the view. Balloons and parts list are linked — renumber a component in the parts list and its balloons update automatically.

The parts list can be customised to show whichever iProperties columns are relevant: part number, description, quantity, material, supplier reference, or custom fields you’ve added to the model properties. For a purchased components list, including the supplier part number and preferred supplier in the parts list saves the purchasing team the effort of cross-referencing specifications.

Managing Drawing Revisions

Manufacturing drawings require revision control. Inventor supports revision tables placed in the drawing border area, with fields for revision number, description of change, author, date, and approval signature. When you issue a revised drawing, you add a row to the revision table with the change description and increment the revision number in the title block.

For teams using Autodesk Vault alongside Inventor, the revision management is integrated with the Vault lifecycle — drawings are checked in and out, revision numbers are controlled by the Vault workflow, and drawing releases are tracked in the electronic vault rather than in paper systems.

Exporting and Printing Drawings

Inventor drawings can be printed directly or exported to PDF for distribution. When exporting to PDF, ensure that the drawing standard (first angle vs. third angle projection symbol) is visible in the title block, and that the sheet scale is included — contractors and sub-vendors sometimes print PDFs at non-standard scales, causing dimensional errors if they try to scale from the print rather than reading the dimensions. A note stating “Do not scale this drawing” in the title block is standard practice.

For sending drawings to DXF or DWG format (for CNC programmers or suppliers who use AutoCAD-based systems), Inventor can export individual drawing views as 2D geometry that retains all annotation and dimension information.

Summary

Inventor’s drawing environment provides everything needed to produce manufacturing drawings that comply with international standards and communicate design intent unambiguously to the workshop. The live parametric link to the 3D model ensures that drawings stay in sync with the design as it evolves, and the comprehensive annotation toolset — tolerances, GD&T, surface finish, weld symbols, thread notes — covers the full range of information that fabricators and machinists need to make parts to specification.

If you’re ready to start producing professional manufacturing drawings, Autodesk Inventor Professional is available from GetRenewedTech at £39.99. Teams working across design, simulation, and manufacturing documentation may also find the Autodesk PDMC Collection at £149.99 the most cost-effective route to the full Autodesk mechanical engineering toolchain.