2D or 3D — Drafting Millwork

Ask ten millwork drafters whether to model a job in 3D and you get two camps, both certain. One says every job, because a model catches what a flat elevation hides. The other says a model eats a day on a run of boxes that never needed it. Both are right about some jobs. This chapter is about telling which job you have.

What the standard asks for is flat

Start with the deliverable, because it settles half the argument. The submittal is a set of 2D sheets, however you make them.

AWI 100, the Architectural Woodwork Institute's submittal standard, tells the manufacturer to "show each component of Product in plan, elevation, and section view as needed to clearly indicate the Product being provided, its location, and its method(s) of construction and attachment." It sets a universal minimum scale for each view:

View	Ratio	Imperial
Reference plan	1:50	1/4" = 1'-0"
Plans and elevations	1:20	3/8" = 1'-0"
Sections	1:10	1 1/2" = 1'-0"
Details	1:4	3" = 1'-0"

Sheets run from a minimum of 11" × 17" to a maximum of 24" × 36", numbered in sequence and dated, and the standard allows them as PDF electronic submittals. Nothing in that list is a model. A reviewer marks up paper or a PDF, and the stamp goes on a sheet.

So 3D is a method, not a deliverable. The question is never "do we send a model". It is "does building a model first make the flat sheets better, faster or safer for this job".

Where pictures do appear in a set

The Woodwork Institute's own 26-sheet sample set is almost entirely orthographic: plans, elevations, sections, details. Pictorial views show up in two places, and both are instructive.

An isometric of a cabinet run used as an index. Callout bubbles on the isometric point to the typical joinery details on the following sheets. The picture tells a reader where each detail lives on the object. The details still carry the construction.
A small isometric of a drawer box, beside the orthographic details of its bottom, sides and back. The picture shows how the parts go together; the details give the sizes.

That is the pattern worth copying. A 3D view helps a reader understand an assembly. It does not replace the section that dimensions it.

The case for 3D, as the trade makes it

Build it in 3D. So many mistakes were missed when working 2d. autocad 3d is very easy. Extrude, Press, Slice is really all you need.
A millwork drafter, answering a new drafter on r/Millwork

The argument rests on one fact of drawing: a flat view can agree with itself and still describe something that cannot exist. The Student Handbook for Basic Drafting shows this with a slotted block. Drawn in front and side view only, the slot could be one of several shapes, and every one of them matches both views. Only the top view resolves it. A model has no such gap: a solid has one shape.

In millwork the same failure shows up as interference. The things a 2D set hides most often are the things that happen at a corner or in motion:

Two drawers that meet at an inside corner and cannot both open.
A door that swings into a handle, a light fitting or the next door.
A hinge plate and a drawer runner that want the same patch of a side panel.
A fixing that lands in a gap between studs, or on a service run.
A worktop overhang that clashes with a window reveal drawn on a different sheet.

Each of these is visible in a single elevation only if the drafter already suspects it. In a model it is visible because two solids occupy the same space.

The second argument is the client. On r/cabinetry, a cabinetmaker from central Europe put it plainly: once you bring a 3D view, "the most common phrase is 'I didn't picture it like that. Could we change this and this'." That is a cost if you count it as rework. It is a saving if the change arrives before the shop cuts anything.

The third argument is the machine, and it is the strongest. In manufacturing software, the model is not a picture of the job: it is the job. Cabinet Vision, as its listing on Blum's software-partner page describes it, generates cut lists, bills of material and machine-ready code for CNC routers, point-to-point machines and panel saws. Microvellum says its Toolbox produces machine-ready code and shop drawings from the same model. When the shop runs on that chain, a model is not an extra step. Skipping it means someone re-enters the job by hand. Chapter 27 covers the software.

An outsourcing vendor, HitechDigital, lists 3D visualisation as the first of its "trends": it "enhances conflict detection". Read that as a seller's claim, but it matches what the drafters above report.

The case against, as the trade makes it

The same threads carry the other side.

Time. A commenter on r/woodworking notes that Fusion 360 can make drawings from a model, "which are... OK. Legible." and that modelling is "rather slow" for someone who does not model daily. A model-derived sheet still needs a person to choose which dimensions matter, clear the clutter and add the notes. That work does not go away.
Understanding. An engineer in the same thread warns that a CAD package "can make drawings from a model in seconds, but understanding those drawings isn't as easy." A drafter who has never drawn a section by hand may not see what a generated one is missing.
Repetition. The r/cabinetry cabinetmaker separates new builds, where "everything is repetitive", from renovations of old houses, where "everything is customized". A kitchen of standard boxes in a square room has little to collide, and a shop with its own standard units already knows how they go together.

None of the critics say 3D is useless. They say it is a cost, and a cost has to buy something.

The test: what does this job risk?

Put the argument aside and look at the job. The table is a way of thinking, not a standard; no published source sets these thresholds, so use it to start a conversation with your shop.

Feature of the job	Leans 2D	Leans 3D
Geometry	Rectangular boxes, square walls	Curves, splays, raked ceilings, stairs, anything off-axis
Corners and junctions	Few, and all standard	Inside corners with drawers or doors on both legs; junctions with stone, glass or metal
Moving parts	Doors and drawers on open runs	Fronts that meet, lifts, pocket doors, pull-outs near walls or appliances
Services	None inside the joinery	Lighting, power, data, plumbing or ventilation running through it
Shop workflow	Manual cutting from a cut list	CNC fed from manufacturing software, where the model is the program
Client	Approves from elevations without trouble	Struggles to picture it; high-value, one-off, emotional
Repetition	The same unit forty times	One object, never to be made again

If most of a job sits in the left column, draw it flat and spend the saved time on the sections. If one feature sits in the right column, model that part. If most of it does, model the job.

The middle path: model where the risk is

The choice is rarely all or nothing. Most jobs have one or two places where a 2D set is likely to lie: the inside corner, the curved end, the unit with the lift and the light. Model those. Draw the rest flat. Use the model to prove the awkward junction, then cut sections through it and put them on the sheet with dimensions.

This is also how you learn. A new drafter who models the one tricky corner of every job builds the habit of looking for interference, without spending a week modelling carcasses nobody doubts.

Worked example: two jobs, same week

Job A: a staff kitchen

Eight base units and six wall units along one straight wall, laminate top, no appliances inside the joinery apart from an under-bench fridge in an open space.

Geometry: rectangular. Corners: none. Services: a power outlet above the top.
Risk: the fridge opening size and the dimension string closing to the wall-to-wall measure.
Decision: 2D. Plan, elevation, a typical section through base and wall unit, a detail at the fridge opening and at each end panel. Check the string closes.

Job B: a reception desk

A curved front, a raised transaction ledge, a lower accessible section, cable management to three workstations, and an LED strip under the ledge.

Geometry: curved. Junctions: the ledge meets the curved face; the lower section meets the higher one. Services: power, data and a lighting driver inside.
Risk: the curve's radius against the sheet sizes and bending method; the lighting channel colliding with the ledge support; cable routes through fixed panels.
Decision: model the carcass and the ledge. Cut sections at the high and low ends and at each workstation. Use an isometric as a key to the details, as the Woodwork Institute sample does. The accessible section's heights come from the applicable code, not the model (see chapter 22).

Same drafter, same software, opposite answers. The job decided.

What to check when sheets come from a model

Model-derived drawings fail in their own ways. Check these before issue, in addition to the usual self-check (before you issue):

The model and the sheet agree. After a mark-up, was the model revised and the views regenerated, or was a dimension overwritten on the sheet? An overwritten dimension is a lie the model does not know about.
Dimensions are chosen, not dumped. Automatic dimensioning gives every edge a number. The shop needs the ones it sets out from. Clutter hides the one that matters.
Sections cut where the construction changes, not where the software put a default cut line.
Hidden lines are deliberate. Generated views can show every edge behind the face, or none. Show what the reader needs to understand the construction.
Renders are labelled as renders. A shaded picture is not a construction document. If one goes in the set, say it is for illustration.
Scales meet the specification. Where AWI 100 applies, check each view against its minimum scale. Software will print a section at whatever scale fits the viewport.
Material thicknesses in the model match the specified stock. A default panel thickness in a library is an assumption, and it flows straight into every cut list.

What to check when you draw flat

Every inside corner: draw both legs in plan with fronts open, or state the filler that keeps them clear.
Every door and drawer next to a wall, appliance or another front: show the swing or the extension in plan.
Every object with a service inside it: a section through the service route.
Any view pair that could describe two different objects: add the third view or a section.
Any junction with another trade: a detail at a scale the shop can build from, with the tolerance owner named.

The short answer

The submittal is flat either way. Model when the job's risk sits in geometry, motion, services or a machine that needs the model as its input. Draw flat when the job is rectangular, repetitive and cut by hand. Model the risky part of everything else. And whichever you choose, the sections carry the construction.

Sources

AWI 100 – Submittals, 3.2 Manufacturer/Supplier Responsibility, Architectural Woodwork Institute, awinet.org/standards/requirements-category/manufacturer-supplier-responsibility/ — plan, elevation and section requirement; minimum scale table; sheet size range; PDF submittals. Primary.
Woodwork Institute sample shop drawings, 26 sheets, watermarked SAMPLE, fictitious names — the isometric used as a detail index and the drawer-box isometric. Document.
Student Handbook for Basic Drafting (ptech_drafting_handbook_new.pdf) — multiview projection and the two-view ambiguity example. Primary (a drafting textbook, general drafting).
r/Millwork, "Millwork drafting" — "Build it in 3D" reply. Reported.
r/cabinetry, "Looking for a Millwork Shop to Partner With on Drafting Workflow Research" — client reaction to 3D; new builds repetitive, renovations custom. Reported.
r/woodworking, "How did you learn to draft?" — model-generated drawings "OK. Legible"; modelling slow; understanding generated drawings. Hobbyists and an engineer, not millwork drafters. Reported.
Blum, software partners: Hexagon CABINET VISION, blum.com — cut lists, bills of material, machine-ready code. Vendor description on a partner page. Claimed.
Microvellum, microvellum.com — Toolbox produces machine-ready code and shop drawings. Claimed.
Ripudaman Singh, "Essential Details You Should Look For in Millwork Drawings", hitechdigital.com, 2 July 2024 — 3D visualisation "enhances conflict detection". Outsourcing vendor. Claimed.

The job-risk table and the worked example are reasoning from these sources, not a published rule. No source was found that measures how long modelling takes against drawing flat, or how many errors it prevents; that claim is left out.