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Dimension

Put a measurement on the drawing.

Keyboard: D

How to use it

  1. Click the body of an edge and it dimensions all of that edge, end to end. One click, and it is the one to reach for. Before you click, the edge it will take is lit, with a dot at each end and its length beside it.
  2. Or click two points - corners, midpoints, centers, points on an edge - and it measures between them. Both points get a dot, and the distance shows as you go.
  3. Then move away from what you measured and click again to put the line where you want it. It goes the way the mouse goes: off the top edge of a box, move up and it stands up above the box, move over the top and it lies on the top, move out in front and it goes out in front. It keeps to the plane it is on until the mouse is clearly heading another way.

Circles and arcs

Hover a circle and it lights with its diameter; hover an arc and it lights with its radius, the center marked. Click, move around the curve to turn the line to where it reads best, and click again. It is written DIA 4'-0" or R 4'-0".

A corner of the little straight pieces a curve is drawn with takes the curve, not the corner. Its quadrant points, its center and an arc's two ends are still points - click one to measure from it to something else.

Typing a new size into a radius or a diameter does not resize the circle yet: draw the circle again at the size you want.

Two corners clicked, then the dimension line pulled out clear of the box and set down reading thirty feet.
Corner, corner, then out - the third click is the one people do not expect, and it is the one that decides where the line sits.

It has to measure something

A dimension wants a corner, a midpoint, a center, or a point on an edge at each end. It will not lie across blank paper: a number measuring nothing cannot be driven by the drawing and will never update when the drawing changes, which makes it worse than no number at all.

In SketchUp the way round that is to draw a temporary line where you need it, dimension to that, and rub the line out afterwards - or to use the tape measure, which will measure anything anywhere and leave a guide behind.

Changing one

Pick a dimension and type a new length, or use /resize. The drawing moves to match the number - the geometry follows the dimension, not the other way round - so a wall told it is 12'-6" becomes 12'-6".

Drag one with the move tool to shift the line off to one side without changing what it measures - it follows the mouse the same way it did when it was placed. A radius or a diameter sits on its curve and does not move off it.

How it is written

In whatever the drawing is set to, rounded to the ROUNDED TO setting on the SETTINGS menu - sixteenths unless you say otherwise. /units swaps between feet-and-inches and millimeters, and every dimension on the sheet changes with it.

See also