How to draw a revision cloud in AutoCAD comes down to one command, REVCLOUD. A revision cloud is not decoration: it marks the region that needs changing during a drawing review, and in a design office it is what the reviewer leaves behind for the drafter.
The command is easy to call but has one quiet failure that most tutorials get wrong: the arc size. One digit out and the cloud prints as a black smear, or stops looking like a cloud at all. To learn modelling and documentation end to end, see the AutoCAD for construction course.
The REVCLOUD command in AutoCAD: one prompt, eight options
Type REVCLOUD and press Enter. The first line asks nothing — it reports the current state, and it is the line to read before clicking anything.
| Command line | Meaning |
|---|---|
Minimum arc length: 1715.7829 Maximum arc length: 3431.5659 | The arc size in use, in drawing units |
Style: Normal Type: Rectangular | The current line style and construction type |
Specify first corner point or [Arc length/Object/Rectangular/Polygonal/Freehand/Style/Modify/Layer] <Object>: | Pick the first corner, or type the letter of an option |
Those eight options fall into three groups. Four are construction methods: Rectangular, Polygonal, Freehand and Object. Two are adjustments: Arc length and Style. The last two are Layer, to set the layer, and Modify, to replace a section of a cloud already drawn.
So most of how to draw a revision cloud in AutoCAD is reading that first line, then picking one of the four methods below.
Four ways to create a cloud, and when to use each
All four produce the same thing — a revision cloud — but the number of points you must click differs sharply.
| Method | What you click | Use it when |
|---|---|---|
Rectangular | Two opposite corners | The default, and quickest during review |
Polygonal | Each vertex in turn | The region is not a rectangle |
Freehand | Drag along the path you want | Following an existing curved outline |
Object | One closed shape already drawn | A circle, ellipse, closed polyline or closed spline exists |
The current type is stored in REVCLOUDCREATEMODE: 0 is Freehand, 1 is Rectangular, 2 is Polygonal. A fresh installation is set to 1, so calling the command and clicking two points gives a rectangular cloud straight away.
The Object method is the tidiest and the least used. Draw a circle around the area, call REVCLOUD, type O and click that circle. Autodesk states plainly that the command accepts a circle, ellipse, closed polyline or closed spline, on the REVCLOUD (Command) page.
If the arcs bulge the wrong way, there is no need to delete and start again. The command offers a reversal step: type Y at the Reverse direction prompt and the arcs flip to the other side.
Arc size: the number that decides whether the cloud reads
This is where most attempts fail, and where many tutorials are simply wrong. The Arc length value is not a radius. The command reference defines it as "an approximate value for the chord length of each arc", and explains it in the same breath: the distance between the endpoints of the arc. That is a chord.
The distinction is not pedantry. Anyone who reads it as a radius types a number half the size of what they need, and the cloud comes out twice as dense as intended. Chord length and arc length are two different things too — see How to measure an arc in AutoCAD.
The second point, equally often missed: arc size is in drawing units. A building drawing in millimetres needs arcs in the thousands. The default on a fresh drawing is a mere speck at that scale, so it has to be reset almost every time.
| Arc size | Result on a 1:100 building drawing |
|---|---|
| Single digits | A cloud the size of a grain of rice, invisible until you zoom |
| 500 | Teeth like a comb; prints as a black smear |
| 1500 | Reads clearly as a cloud at 1:100 |
| 4000 and up | Arcs bulge out and lose their teeth, so the cloud stops standing out |
To change the arc size of a cloud already drawn, there is no need to redraw it: select it and call REVCLOUDPROPERTIES. That command does exactly one job — change the chord length of the selected cloud.
Put clouds on their own layer, then clear them in one move
A revision cloud is a temporary note. Once the drawing is corrected the clouds have to go, and that is when setting a layer up front pays off.
The wrong way, and the common one: draw clouds on whatever layer happens to be current, then hunt them down one by one. The right way costs one declaration:
- Make a layer for review notes, say
08-NOTES, in a colour that stands out. - Type
REVCLOUDLAYERand press Enter, then give that layer name. - Every later cloud lands on that layer with no manual switching.
- When the drawing is corrected, turn off or delete one layer and every cloud is gone.
The default value of this variable is a dot, meaning use the current layer. Any other value overrides the current layer, but it applies only to clouds made with the REVCLOUD command. This variable is new in the 2026 release, so older tutorials do not mention it.
The same release added REVCLOUDSCALEMODE, which scales arc length by DIMSCALE. If DIMSCALE is already right for the plot scale, the arc size takes care of itself. The full list is on the Commands for Revision Clouds page.
Two old variables are obsolete — stop setting them
Plenty of guides still tell you to set REVCLOUDMINARCLENGTH and REVCLOUDMAXARCLENGTH for the minimum and maximum arc size. Autodesk has marked both of those obsolete.
The current release works differently: a single value is stored in REVCLOUDAPPROXARCLEN, and REVCLOUDARCVARIANCE then decides whether the arcs vary.
| Value | Result |
|---|---|
REVCLOUDARCVARIANCE set to 1 | The default. Arcs vary, giving a hand-drawn look |
REVCLOUDARCVARIANCE set to 0 | Arcs are uniform, giving a tidier mechanical look |
That is why the command's first line reports two figures, a minimum and a maximum, even though you only ever set one. Those two figures are an outcome, not two separate things to declare.
A revision cloud is a polyline, so edit it like one
The last point, and the one that opens up the most. Autodesk states it directly: "Revision clouds are closed polylines that form cloud-shaped objects consisting of arc segments." A cloud is a closed polyline made of arc segments.
What follows from that in practice:
- Select a cloud and open the Properties palette with
Ctrland1to read both the area and the perimeter of the region you enclosed. - Every polyline edit works:
PEDIT, dragging grips,MOVE,COPY,SCALE. - How many grips appear on a selected cloud is governed by
REVCLOUDGRIPS. A cloud with many arcs and every grip showing clutters the screen, so lowering that value makes selection easier. - To rework one section rather than the whole cloud, use the
Modifyoption inside the command: it replaces a stretch of the cloud with a new one you draw.
One habit worth adopting on drawings that go through several review rounds: give each round its own cloud colour, with the round number beside the cloud. The drafter can then tell at a glance which round a note belongs to, without looking anything up.
Put together, that is how to draw a revision cloud in AutoCAD and keep it useful: the right method, an arc size in drawing units, and a layer of its own so the clouds come off again in one move.
Frequently asked questions
Which command draws a revision cloud in AutoCAD?
REVCLOUD. Type the full command name and press Enter, or click the Revision Cloud button on the Draw panel of the Home tab.
Why does my cloud come out tiny, or dense as a black smear?
The arc size is wrong. Arcs are measured in drawing units, so a millimetre-based building drawing needs arcs in the thousands. Type A and set the value again.
Is the Arc length value a radius or a chord?
A chord — the distance between the endpoints of each arc. This is the point many tutorials get wrong by calling it a radius.
How do I clear every revision cloud once the drawing is corrected?
Set REVCLOUDLAYER to a dedicated layer before you start. When the work is done, turning that one layer off clears them all.
Can I change the arc size of a cloud I already drew?
Yes. Select it and call REVCLOUDPROPERTIES, which changes the chord length of the selected cloud without redrawing it.
Is a revision cloud its own kind of object?
No. It is a closed polyline made of arc segments, so its area shows in the Properties palette and every polyline edit applies to it.
Related articles
- How to measure an arc in AutoCAD — telling chord, arc length and radius apart
- How to draw an arc in AutoCAD — eleven construction methods and the radius trap
- Construction drawing symbols — the conventions used across a drawing set
- What is AutoCAD — a handbook for people working in construction