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The ZOOM command in AutoCAD, and three jobs people confuse with it

The zoom command in AutoCAD changes the view, not the drawing. Learn how ZOOM differs from SCALE and DIMSCALE, plus the X suffix and the XP factor.

  • Assoc. Prof. Tran Anh Binh
  • 9 min read
Three different jobs all called zooming in and out, and the three commands that do them Photo: Diagram by the Institute of Information Technology in Civil Engineering

The zoom command in AutoCAD changes where you stand to look, not the drawing itself. It is the most repeated action of the working day — repeated so often that it belongs on the mouse rather than on the keyboard.

Before going into ZOOM, one thing needs settling. Three very different jobs in AutoCAD all get called "zooming in and out", and picking the wrong one damages the drawing rather than merely wasting time. This article separates those three, then goes deep on ZOOM. To learn modelling and documentation end to end, see the AutoCAD for construction course.

Three jobs that all get called zooming

What you wantThe right commandDoes the drawing change?
To see something more clearlyZOOMNo. Only the viewpoint moves
To make geometry actually bigger or smallerSCALEYes. Measure it again and the number differs
Dimension figures too small on paperThe DIMSCALE variableGeometry unchanged; only the annotation size

The middle row causes most of the trouble. Someone who needs to shrink an object and reaches for ZOOM watches it get smaller on screen, then measures it and finds the original number — because ZOOM never touches geometry.

The last row is the same trap in reverse: geometry at the right size but dimension text printing tiny. That belongs to DIMSCALE, an overall factor applied to the text height and arrow size of a dimension style. Autodesk explains it on the About Setting the Scale for Dimensions page.

The rest of this article is about ZOOM.

Use the mouse first, the command second

View control belongs on the mouse. Learn these four lines and most of the work is covered.

ActionResult
Roll the wheelZooms around the cursor. Move the cursor to what you want first, then roll, and you never have to pan back
Hold the wheel and dragPans the view. This is the PAN command; the mouse is quicker than typing its name
Double-click the wheelFits the whole drawing to the screen — the same as Zoom Extents
Type Z then EZoom Extents again. Two characters worth memorising, for whenever you lose the drawing

Wheel-dragging works because MBUTTONPAN is set to 1. How much one notch of the wheel magnifies is set by ZOOMFACTOR, which defaults to 60. If the wheel feels too jumpy, drop it to around 20 to 30 and the motion becomes far smoother. The detail is on the ZOOMFACTOR (System Variable) page.

If the screen glides for a beat on every zoom and you would rather it snapped, that is the smooth view transition controlled by VTENABLE. It defaults to 3 and accepts 0 to 7, summed from three bits: 1 for panning and zooming, 2 for view angle changes, 4 for scripts.

Set it toResult
2Transitions off for zoom and pan, still on for view angle changes
0Every view transition off
3The default, on for both

2 is usually the right choice: zooming responds instantly while orbiting a 3D view stays smooth. The VTENABLE (System Variable) page lists all eight values.

The eight options of the ZOOM command

Type ZOOM, or the alias Z, then press Enter. The prompt runs to two lines and holds every option.

Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>:

The default in angle brackets is real time: press Enter straight away and you drag the mouse to zoom. Hold the left button and drag up to magnify, down to shrink, Esc to leave.

TypeOptionWhat it does
AAllShows the LIMITS area as well as every drawn object
CCenterAsks for a centre point, then a view height
DDynamicDrag a frame over the whole drawing to choose what to view. Predates the scroll wheel and is now rarely used
EExtentsEvery object fits the screen. The one used most
PPreviousSteps back to the previous view. Twenty are remembered
SScaleAsks for a factor. Read the next section before using it
WWindowFrame an area with two corners
OObjectSelect objects and they fill the screen
Zoom Center and Zoom Scale Photo: Left: Zoom Center with a chosen centre and a view height of 9000. Right: Zoom Scale 0.5X, the plan at half the previous view

All eight also sit on the drop-down of the Zoom button on the navigation bar, at the right-hand edge of the drawing area.

The Zoom menu on the navigation bar Photo: The Zoom drop-down carrying all eight options of the command, plus Zoom Realtime, Zoom In and Zoom Out

The X suffix: the slip that loses your drawing

This is what leaves people staring at a blank screen after Zoom Scale, convinced the drawing has gone.

With an X, the number is relative to the view you are in now. 2x always doubles the magnification from wherever you are, however many times you repeat it. 0.5x halves it.

Without an X, the number is relative to the LIMITS area. On a building drawing LIMITS usually bears no relation to the plan, so the result lands somewhere unpredictable.

A concrete case shows the scale of it: on a drawing whose LIMITS are 420 by 297, typing a bare 2 gives a view 148 units high — smaller than a single brick. A plan 21600 long is then entirely off screen.

The safe rule: always type the X, unless you know exactly what the drawing's LIMITS are.

To prove it to yourself, use VIEWSIZE, which stores the height of the current view in drawing units. Read it before and after each command and you can see what the command did:

  1. Type VIEWSIZE and press Enter. Write the number down.
  2. Type Z, Enter, then 1x, Enter. Read VIEWSIZE again: unchanged. A factor of 1x means keep as is.
  3. Type Z, Enter, then 2x, Enter. VIEWSIZE is now exactly half. Half the view height means twice the magnification.
  4. Type Z then E. The whole drawing fits, and VIEWSIZE jumps to the real height of the drawing.

Step 2 is the test worth running: if the number moves, your reading of the X suffix is wrong.

The XP factor: setting viewport scale in a layout

There is a second factor, and it belongs only in a layout. XP means relative to paper space, not to the current view.

To set the scale of a viewport:

  1. Type MSPACE to step inside the viewport.
  2. Type ZOOM and press Enter.
  3. Type 1/100XP and press Enter. That viewport is now at 1:100.

This is the older method but it still works, and it shows that viewport scale is simply a number. Two more modern routes: select the viewport from paper space and read the Viewport Scale box on the status bar, or open the Properties palette and set Standard scale. Properties is the most reliable because the number can be read back.

PAN, and the version with a minus sign

Holding the wheel and dragging covers most panning. But the PAN command has two versions for two different jobs.

Type PAN and press Enter: the cursor becomes a hand, you hold the left button and drag, then press Esc. This is the by eye version, with no numbers in it.

Type -PAN, minus sign first: no hand this time. The program asks for a base point and then a second point. Enter 0,0 then 3600,0 and the view slides exactly one column bay, no more and no less.

The minus version is the only one that can be written into a script file, because a script cannot drag a mouse.

When the wheel stops shrinking the view

If rolling the wheel no longer makes anything smaller, you have hit the zoom-out limit of the current view. Type Z then E to jump back to the actual extents of the drawing.

If Z E still shows nothing — or shows the drawing as a speck in one corner — there is an object sitting far from the origin, usually pasted in by accident. Zoom Extents has to enclose that stray object, so the real plan gets squeezed to nothing.

To find it: type Z then E for the overview, then window-select the far region to see what is there. Delete the stray object, run Z E again, and the drawing behaves normally.

Frequently asked questions

What is the alias for the zoom command in AutoCAD?

Type Z and press Enter, then the letter of the option — E for Extents, W for Window, and so on.

How do I shrink an object in AutoCAD?

That is not ZOOM but the SCALE command. ZOOM only moves the viewpoint; measure the object afterwards and it is unchanged.

Why does Zoom Scale make my drawing disappear?

Because the factor was typed without an X. A bare number is relative to LIMITS, which rarely matches a building plan. Always include the X.

The mouse wheel jumps too far — where do I change it?

Type ZOOMFACTOR and set it to somewhere around 20 to 30 instead of the default 60.

Zoom Extents runs but the drawing is a speck in the corner. Why?

An object is sitting far from the origin, usually pasted in by mistake. Find it, delete it, then run Z E again.

About the author

Assoc. Prof. Tran Anh Binh — Director of the Institute of Information Technology in Civil Engineering – Hanoi University of Civil Engineering