A round column on a floor plan, a pile head symbol, a dot marking a control point. All three are either a filled circle or a ring, and drawing them as two circles with a hatch between is both slow and heavy on the file.
The donut command in AutoCAD produces exactly that shape as a single object. But the object is not a circle, and its area field reads wrong unless you know what the program is actually measuring. For the whole drawing toolkit see our AutoCAD for Construction course.
Where to start it
Read from the acad.cuix interface file and the acad.pgp file of the 2027 release.
| Way in | What to use |
|---|---|
| Full command | DONUT |
| Alias | DO |
| Other spelling | DOUGHNUT |
| Ribbon | Home → Draw → Donut |
| Classic menu | Draw → Donut |
| Toolbar | none |
Unlike the solid modelling commands, this one is well served: a ribbon button, a menu item and a two-letter alias. DOUGHNUT is simply the full English spelling and reaches the same command.
The steps on the command line
Copied verbatim from AutoCAD 2027.
Command: DONUT
Specify inside diameter of donut <200.0000>: 200
Specify outside diameter of donut <500.0000>: 500
Specify center of donut or <exit>:
Specify center of donut or <exit>:| Step | What it asks | What you do |
|---|---|---|
| 1 | Specify inside diameter of donut <200.0000>: | Give the inner diameter |
| 2 | Specify outside diameter of donut <500.0000>: | Give the outer diameter |
| 3 | Specify center of donut or <exit>: | Pick a centre |
| 4 | the same prompt again | Pick another centre, or Enter to finish |
Step four is the handiest part and the most overlooked: once the two diameters are set, the program keeps asking for centres. Placing forty identical pile head symbols means forty clicks, not forty runs of the command.
Note also that the inside diameter is asked for first, before the outside one. That order catches people used to describing a pipe the other way round. Typing the larger figure at the first prompt is the commonest slip with the donut command in AutoCAD — though, as the measurements further down show, it does no harm at all.
The two figures in angle brackets are what was used last time. They live in the variables DONUTID and DONUTOD, so pressing Enter twice keeps the previous size.
A wide ring is really a closed polyline
This governs everything else, and hardly any tutorial mentions it.
Set the inner diameter to 200 and the outer to 500, then read what appears:
| What was read | Value |
|---|---|
| Object type | one closed polyline |
| Vertices | 2 |
| Line width, that is (500 − 200) / 2 | 150 |
| Bounding box, that is (200 + 500) / 2 | 350 |
| Length, that is π × 350 | 1,099.557 |
There is no circle in the drawing at all. Autodesk's DONUT page says as much: "The width of the polylines is determined by the specified inside and outside diameters." The program draws a centreline circle of diameter 350 — the mean of the two diameters you gave — and gives that line a width of 150, half the difference between them. The width sits evenly either side of the centreline, 75 each way, so the inner edge lands exactly on 200 and the outer edge exactly on 500.
The practical consequence: the bounding box is 350, not 500. Anyone using the bounding box to align things or to work out spacing will be 150 out.
The trap in the area field
Select the ring just drawn, open the Properties palette, and the area field reads 96,211.275.
That is not the area of the ring. The real area of the ring is what lies between the two edges, π × (250² − 100²), which is 164,933.61. The figure of 96,211.275 is exactly π × 175² — the area of the circle bounded by the centreline.
| Figure | Equals | What it is |
|---|---|---|
| The area field in Properties | 96,211.275 | π × 175², the circle on the centreline |
| The true area of the ring | 164,933.61 | π × (250² − 100²) |
Nearly 71% apart. The reason is the same as before: the program treats this as a polyline, and for a closed polyline the area field always follows the centre of the line, ignoring its width. For the true ring area you have to work it out yourself, or draw two circles and measure — covered in our article on measuring areas in AutoCAD.
Giving the two diameters the wrong way round is harmless
Try it completely backwards: inner 600, outer 300.
| What was read | Value |
|---|---|
| Object type | one closed polyline, 2 vertices |
| Line width | 150 |
| Bounding box | 450 |
No error, and nothing strange on screen. The result is identical to giving 300 and 600 in the proper order: centreline 450, width 150, inner edge 300, outer edge 600. The program simply takes the mean and half the absolute difference, and sorts out for itself which figure was meant to be the larger.
An inner diameter of zero gives a filled circle
This is the quickest way to draw a solid dot in AutoCAD.
Give an inner diameter of 0 and an outer of 500:
| What was read | Value |
|---|---|
| Line width, that is (500 − 0) / 2 | 250 |
| Bounding box, that is (0 + 500) / 2 | 250 |
The rule holds unchanged; the inner edge has simply collapsed onto the centre, so the hole disappears. Autodesk states the same outcome: "If you specify an inside diameter of 0, the donut is a filled circle." The dot has the outer diameter of 500 you asked for, but its bounding box still reads 250.
A dot like that serves for pile heads, control points and survey marks, and it is far lighter than a circle plus a patch of hatching. One object instead of two, and no hatch boundary to break later on.
The FILLMODE variable only changes the display
Draw a ring, set FILLMODE to 0 and run REGEN, and on screen the ring changes completely: no longer solid, just two edge circles with hatching lines between them.
The object, though, does not change at all:
| FILLMODE = 1 | FILLMODE = 0 | |
|---|---|---|
| Object type | closed polyline, 2 vertices | closed polyline, 2 vertices |
| Line width | 150 | 150 |
| Bounding box | 350 | 350 |
| Length | 1,099.557 | 1,099.557 |
Every figure identical. The FILLMODE variable governs only how the object is painted on screen and on paper, and never touches the geometry. So when a drawing arrives from elsewhere with rings that look hollow, do not start editing shapes — check this setting first. Note that changing it takes a REGEN before the screen follows.
What rings and dots are good for
The places they come up most in construction drawings:
Pile head symbols on a foundation plan. A dot or a ring, laid out in bulk thanks to the repeating prompt at step four.
Reinforcement in section. A filled circle at the true bar diameter, with no circle to draw and no hatch to add.
Setting-out marks, control points, grid intersections. A thin ring reads more clearly than a cross when the drawing is dense.
Pipes cut in section. Give the true inner and outer diameters of the pipe and the wall section appears at once.
Because the result is an ordinary polyline, every familiar command works on it: COPY, ARRAY, SCALE, and PEDIT to change the line width afterwards. Editing polylines is covered in our article on polylines in AutoCAD.
Five things people say that are not true
| What people say | What the 2027 release actually does |
|---|---|
| A ring is two circles put together | It is one closed polyline of 2 vertices, width (OD − ID) / 2 |
| The bounding box equals the outer diameter | It equals the mean diameter: 200 and 500 give a box of 350 |
| The area field gives the ring area | That field reads π × 175² = 96,211.275; the ring is really 164,933.61 |
| Reversing the two diameters is an error | The program sorts them out: 600 and 300 gives what 300 and 600 gives |
| FILLMODE 0 makes the ring hollow | It only changes the display; width, box and length are unchanged |
Frequently asked questions
Is there an alias?
Yes, DO. Typing DOUGHNUT reaches the same command.
How do I draw a solid dot?
Run the command with an inner diameter of 0 and an outer diameter equal to the size of dot you want.
Why does the area field not match?
Because the program measures the area along the centre of the polyline and ignores its width. A ring of 200 and 500 shows 96,211.275 where the true area is 164,933.61.
My rings look hollow — where do I fix that?
Set FILLMODE to 1 and run REGEN. Nothing is wrong with the geometry; it is purely how it is drawn.
Can I resize a ring I have already drawn?
Yes. It is a polyline, so SCALE changes both diameters and PEDIT changes the line width on its own.
How do I place many rings of the same size quickly?
Do not end the command. After the two diameters are set it keeps asking for centres until you press Enter.