A pipe, a wheel, a round column base, a water tank: every one of them is a flat shape spun about an axis. Drawing each section and stitching them together is slow and easy to get wrong. The revolve command in AutoCAD does it in one pass: pick the shape, name the axis, type an angle, and the solid is there.
Everything below was measured on AutoCAD 2027 at the Institute, including one test we have not seen anywhere else: taking the volume the software reports and checking it against the formula, to find out whether the number can be trusted. For a proper grounding in modelling, the Institute runs an AutoCAD course for construction.
Where to start it
Before you can use the revolve command in AutoCAD you have to find it, and this is where people first stumble. The table below was read out of the acad.cuix interface file of the 2027 release on the machine, not written from memory.
| Command | Alias | Ribbon | Classic menu | Toolbar |
|---|---|---|---|---|
REVOLVE | REV | none | Draw → Modeling → Revolve | Modeling → Revolve |
EXTRUDE | EXT | none | Draw → Modeling → Extrude | Modeling → Extrude |
PRESSPULL | none | none | none | Modeling → Presspull |
Note that neither of the main modelling commands has a button on the default ribbon. The Drafting & Annotation workspace most people use does not show them. You either switch to the 3D Modeling workspace or type REV, which is faster anyway.
Step by step on the command line
The prompts are copied verbatim from the 2027 release on the machine.
| Step | What the machine asks, verbatim | What you do |
|---|---|---|
| 1 | Command: | Type REV and press Enter |
| 2 | Current wire frame density: ISOLINES=8, Closed profiles creation mode = Solid | This is a status line, not a question |
| 3 | Select objects to revolve or [MOde]: | Pick the profile and press Enter |
| 4 | Specify axis start point or define axis by [Object/X/Y/Z] <Object>: | Click the first axis point, or type Y for the Y axis |
| 5 | Asks for the second axis point | Click it |
| 6 | Asks for the angle | Type 360 and press Enter |
Step two is worth reading rather than skipping. Closed profiles creation mode = Solid tells you a closed shape will come out as a solid. To change that, type MO at step three and switch to surface mode.
Step four offers four routes. Object takes an existing line as the axis, handy when you have already drawn a centreline. X, Y and Z take an axis of the current coordinate system straight away, which is quick but depends on where that system is standing; our article on the UCS in AutoCAD covers that.
Autodesk describes the command in one line on the REVOLVE page for the 2027 release: "Creates a 3D solid or surface by sweeping an object around an axis".
A closed profile gives a solid, an open one only a surface
This is where beginners get disappointed: the revolve runs, and instead of a solid they get a thin shell.
The cause is the profile. Autodesk states it plainly on that same page: "Open profiles create surfaces and closed profiles can create either a solid or a surface".
We measured it and got exactly two outcomes:
| What was revolved | Object type created |
|---|---|
| A rectangle (closed) | 3DSOLID |
| A single line (open) | REVOLVEDSURFACE |
So a closed profile is the requirement for a solid. A shape drawn as separate segments has to be joined into one continuous outline first, with PEDIT, JOIN or REGION. Joining and editing polylines is covered in our article on polylines in AutoCAD.
It is worth knowing what the command will accept. Autodesk's page lists circles, ellipses, arcs and elliptical arcs, regions, 2D and 3D polylines, 2D and 3D splines, traces, 2D solids, and surfaces, along with the edges of existing solids and surfaces. Two things it will not take: objects inside a block, and outlines that cross over themselves. If a revolve refuses to start on an outline that looks closed, a segment crossing over itself is the usual reason, and zooming in on the vertices is how to find it.
The MOde option at the selection prompt is the one people forget exists. Switch it to surface and even a closed outline comes back as a shell rather than a solid, which is what you want when the shape is only ever going to be looked at rather than measured. Switch it back afterwards, because the setting sticks for the rest of the session.
Angle and volume: can the software's number be trusted?
Most tutorials stop at "type 360 and you are done". We wanted one thing more: whether the volume AutoCAD reports is good enough to take off quantities from.
The test runs like this. Take a rectangle 200 × 400 and place it so its centroid sits exactly 200 from the axis. An old theorem of Pappus gives the volume of a solid of revolution as 2 × π × R × A, where R is the distance from the centroid to the axis and A the area of the shape. Putting the numbers in: 2 × 3.14159… × 200 × 80,000 = 100,530,964.9.
Revolving three times at three angles and reading the volume back:
| Angle | The software reports | The formula gives |
|---|---|---|
| 90° | 25,132,741.2 | 25,132,741.2 |
| 180° | 50,265,482.5 | 50,265,482.5 |
| 360° | 100,530,964.9 | 100,530,964.9 |
All three agree to the decimal place. Two things follow.
First, AutoCAD's volume figure is exact, so it can be used for concrete or steel quantities without hand-checking.
Second, volume scales directly with the angle. Ninety degrees gives exactly a quarter, a hundred and eighty exactly a half. That sounds obvious but it licenses a practical shortcut: when you need a quarter of the solid, revolve 90° rather than building the whole thing and cutting it.
The opening figure shows those three. One rectangle, one axis, only the angle changed.
The DELOBJ variable eats your profile
This is the trap that wastes the most time, and one that Vietnamese tutorials barely warn about.
You finish a revolve, decide to spin the same shape at another angle, and the shape is nowhere to be found. The software deleted it.
The culprit is the DELOBJ variable. On our machine its default is 3. Measured both ways:
DELOBJ | After revolving |
|---|---|
| 3 — the default | The profile disappears |
| 0 | The profile stays |
The neat fix is to type DELOBJ, enter 0, and only then revolve. Put it back to 3 afterwards if you prefer a tidy drawing. Or simply copy the profile before revolving, since you will usually want it later for dimensioning anyway.
3D drawing in AutoCAD: where revolve sits
Plenty of people trying 3d drawing in autocad do not know where to begin, because the software has several modelling commands that look alike. Laid out, it is short:
| Command | Use when the profile | Typical example |
|---|---|---|
REVOLVE | spins about an axis | pipes, round tanks, column bases |
EXTRUDE | is pulled straight | beams, square columns, walls |
SWEEP | follows a path | handrails, bent pipe, cornices |
LOFT | joins different sections | hoppers, transitions |
Those four cover almost all solid modelling. The extrude command is the closest relative of revolve: both start from a flat shape, one pulling it straight and the other spinning it round.
That is also the sensible order of learning for anyone in construction: rather than memorising every 3D command, look at the object and ask what operation produced it. Round and symmetrical means revolve; constant section means extrude.
One note on display. If the result still looks flat, you are looking straight down at it. Type -VIEW and choose SWISO for an isometric view, then VSCURRENT and choose Shaded. Without those two steps every solid looks like a rectangle.
Three things tutorials leave out
| What people assume | What the 2027 release actually does |
|---|---|
| Anything revolved becomes a solid | An open outline gives a REVOLVEDSURFACE, a shell |
| The profile survives the operation | DELOBJ defaults to 3, so it is deleted |
| The reported volume is only indicative | Measured three times, it matched the formula to the decimal |
In short, the revolve command in AutoCAD asks three questions: what to spin, what to spin it about, and how far. The real difficulty lies elsewhere: getting the profile closed, and remembering to turn DELOBJ off first.
For construction work it earns its keep on the round details that are tedious to draw by hand: drainage pipes, circular tanks, column caps, bearings. Build one, read the volume, and the quantity is there.
Frequently asked questions
What is the alias?
REV. The command has no button on the default ribbon, so typing it is quickest.
Why did I only get a thin shell?
The outline is open. Join the segments into one closed loop with PEDIT, JOIN or REGION, then revolve again.
Why did my original shape vanish?
DELOBJ is at 3. Type DELOBJ and enter 0 before revolving to keep it.
Do I have to draw an axis line first?
No. Click any two points for the axis, or type X, Y or Z to use an axis of the current coordinate system.
How do I revolve the other way?
Enter a negative angle, or use the Reverse option. Autodesk describes it as "similar to entering a - (minus) angle value".
A revolved solid still looks flat on screen. Why?
You are viewing from directly above. Type -VIEW and pick SWISO, then VSCURRENT and pick Shaded.