Measuring Angles and Distances to Model Precisely

What distinguishes solid construction and design from an M.C. Escher optical illusion? Accurate measurements.

In SketchUp, the Tape Measure tool, the Protractor tool, and the Measurements box enable you to model precisely:

  • With the Tape Measure tool (), you can measure a distance and set precise guide lines or guide points.

    Note: Guide lines and guide points are temporary dashed lines used as guides to draw precisely. They do not interfere with regular geometry.

  • The Protractor tool () enables you to measure angles and set a precise angled guide line.
  • You can enable the Create Guide functionality in both the Tape Measure and Protractor tools by pressing Ctrl on Windows or Command on Mac to toggle it off and on.
  • You can lock the tool functionality to an axis by pressing the corresponding Arrow key before or during operation.
  • As you use almost any tool in SketchUp, the Measurements box is waiting to accept a precise value.

Beyond these tools, you can also combine the tips in this article with a little math to estimate building height accurately.

Table of Contents
  1. Measuring a distance
  2. Measuring an angle
  3. Editing guide lines
  4. Hiding and erasing guide lines
  5. Estimating building height accurately
  6. Measurements box quick reference

Measuring a distance

The Tape Measure tool can measure a distance, create a guide or reveal coordinates along the xis. Here’s where you find the Tape Measure in the SketchUp interface:

  • Getting Started toolbar
  • Construction toolbar
  • Large Tool Set toolbar
  • Tools menu on the menu bar
  • Tools palette (macOS)

Tip: With the Tape Measure tool selected, you can see the length of line or the area of a face at glance. Hover the Tape Measure cursor over a line or face, and you see the distance or area in the Measurements box.

To measure geometry or set a guide line, follow these steps:

Note: A good rule to remember; You'll use endpoints to create Guide Points, you can create Guide Lines using midpoints, lines or faces.
  1. Select the Tape Measure tool () or press the T key.
    Note: The default setting for the Tape Measure tool is to create guide lines and guide points as you measure. A plus sign appears next to your Tape Measure cursor when in guide creation mode (). If you wish to simply measure between two points without creating a guide, you can press Ctrl (Microsoft Windows) or Option (macOS). The plus sign next to the Measure tool disappears in this mode. This mode will persist until you switch tools.
  2. Click the starting point of your measurement. If you need to select an end point or midpoint, the SketchUp inference engine helps you find it. To create a guide line, click a line that needs to be parallel to your guide line.
  3. Move the cursor in the direction you want to measure. As you move the mouse, a temporary measuring tape line, with arrows at each end, stretches from your starting point, as shown in the figure.

    Tip: Here are a few tips to help you move the Tape Measure cursor through 3D space:
    • The measuring tape line changes color to match an axis colors when it is parallel to any axis. In the figure, you see measuring tape aligned to the red axis.
    • Tap a directional button while measuring to lock an axis. The up arrow locks the blue axis, the left arrow locks the green axis, and the right arrow locks the red axis. You'll see a notification at the cursor that the inference is locked.
    • The Measurements box dynamically displays the length of your measuring tape.

  4. Press Esc if you need to start over.
  5. (Optional) To create a guide line, press Ctrl (Microsoft Windows) or Option (macOS). A plus sign appears next to your Tape Measure cursor ().
  6. Click at the ending point of your measurement. The distance from the start point appears in the Measurements box. If you pressed Ctrl in the preceding step, a guide line appears as a dashed line that reaches into infinite 3D space (at least within your model). In the following figure, the guidelines mark the distance 3 feet from the interior walls. (See Adding Text to a Model for information about labeling distances in your model.)
  7. (Optional) To move your guide line a precise distance from the starting point, type a number and unit and then press Enter.

Note: If you measure a distance without creating a guide and then enter a value, SketchUp asks whether you want to resize your model. See Scaling Your Model or Parts of Your Model for details.

Tip: When you measure from an end point inference and create a guide, SketchUp creates a guide point, as shown in the figure. A guide point is a finite dashed line, whereas a guide line is infinite.

Measuring an angle

Measure an angle when you want to duplicate that angle elsewhere in your model or create plans, such as for a woodworking project. To measure an angle or create angled guide lines, use the Protractor tool.

You find the Protractor tool () in a few different parts of SketchUp’s interface:

  • Construction toolbar
  • Large Tool Set toolbar
  • Tools menu
  • Tool palette (macOS)

In the video, you see how to measure angles and set guides with the Protractor tool. For steps that walk you through the process, read the rest of this section.

To measure an angle and create an angled guide line, follow these steps:

  1. Select the Protractor tool (). The cursor changes to a protractor. The center point is fixed to the cursor.
  2. Click to set the vertex of the angle that you want to measure. (See Callout 1 in the figure.) If you need to lock an orientation, press and hold the Shift key before you click.
    Tip: When you press and hold the Shift key to lock/constrain the plane of rotation, you can tap Alt (Microsoft Windows> or Command (macOS) to free the protractor from the inferenced plane. The angle of the protractor will remain the angle of the original plane, but now you can move the protractor to inference other geometry.
  3. Click where the angle that you want to measure begins. (See Callout 2 in in the figure.)

    Tip: You can click and drag from the vertex to the first point to define the axis of rotation. This is especially helpful if you need to rotate on an axis that isn’t on the red, green, or blue planes. Press Esc at any point to start over.

  4. Move the cursor to measure the angle. (See Callout 3 in the figure.)

    Tip: Here are a few tips to help you find the right angle measurement:
    • As you move the cursor, the angle appears dynamically in the Measurements box.
    • When the cursor is close to the protractor, the angle snaps to the protractor’s tick marks, which indicate 15 degree increments. When your cursor is farther from the protractor’s center, you can measure the angle in more precise measurements.

  5. Click to set an angled guide line.
  6. (Optional) Type a value and press Enter to change the angle of your guide line (relative to the start line). You can type a decimal value, such as 34.1, or a slope, such a 1:6. Change this value as many times as you like until you make another selection or choose another command.

Note: SketchUp can handle up to 0.1 of a degree of angular precision.

Editing guide lines

To reorient a guide line or guide point, you can move or rotate it. See Moving Entities Around and Flipping and Rotating for details.

Note: You cannot resize a guide line because guide lines are infinite in length.

Hiding and erasing guide lines

Guide lines are usually created as a temporary aid for building a portion of your model. Keeping too many guide lines in your model can decrease SketchUp’s inference accuracy and display performance, so you might want to hide guide lines as you work or delete all guide lines after you finish your 3D model.

To hide guide lines, you can use either of the following methods:

  • With the Select tool (), select one or more guides and then select Edit > Hide.
  • Context-click a selected guide or guides and select Hide from the menu that appears, as shown in the figure.

To make hidden guides visible again, select Edit > Unhide and choose an option from the Unhide submenu.

Deleting guide lines removes them altogether, never to return. Here are some ways to delete your guide lines:

  • With the Select tool (), select one or more guides and then select Edit > Delete.
  • Context-click a guide and choose Erase from the menu that appears.
  • Click a guide line with the Eraser tool ().
  • Select Edit > Delete Guides to erase all guides in the current context.

Estimating building height accurately

If you don’t know the height of an existing building that you’re trying to model, here are some techniques you can use to make an educated guess:

  • Count repeated units.
  • Take a picture with an object of known height
  • Use trigonometry.

When you’re ready to extrude a building’s footprint to the correct height, make sure you’re in ISO view by choosing Camera > Standard Views > Iso. Then use the Push/Pull tool () to extrude your building into 3D and enter your building's exact height.

Method 1: Count repeated units

Often, buildings are constructed with bricks, blocks or other modular construction materials. Measure the height of a single unit, count the total number of units on the facade, and multiply to get an approximate overall height.

This method also works for entire building levels. If you can measure a single level on the façade of your building, you can multiply by the total number of levels to arrive at an approximate overall measurement.

Method 2: Take a picture with an object of known height

When you’re taking a picture of the building you plan to model, include something (or someone) in the photo whose height you know.

Tip: Here are a few tips for estimating building height with this method:
  • A meter stick or a person works well.
  • Position your “known quantity” as close to the building as possible for accuracy.
  • Take the photo from as far away as possible to minimize vertical distortion.

You can use a photo-editing program to estimate the height of your building based on the object (or person) you included in the photograph.

Method 3: Use some simple trigonometry

With a few simple measurements, it’s possible to estimate heights with some accuracy. Take a look at the figure below. All you need to know is:

  1. Your distance from the building
  2. Your eye height
  3. The angle between the ground and the top of the building

Use this formula to calculate the height of the building:

Height = ( tan(angle) x distance ) + eye height

For example, given a building distance of 25 meters, an angle of 37 degrees, and an eye height of 1.75 meters, the formula would be:

Height = tan(37) x 25m + 1.75m<br>
= 0.75355 x 25m + 1.75m<br>
= 20.6m

Note: On your calculator, the tan button calculates the tangent of an angle.

Measurements box quick reference

In this section, you find tables that outline all the values the Measurements box accepts, depending on what tool you’re using. Remember that, after you use a tool, you can simply type the value and press Enter. You don’t need to click in the Measurements box. Also, until you make another change to your model or select a different tool, you can continue to enter values that modify your action.

Specifying Units of Measurement

The following table outlines how to specify units of measurement. If you don’t indicate a unit, SketchUp uses the units in your template. To see or change your default units, select Window > Model Info and select Units in the sidebar on the left.

Unit How to Specify It Example
Inches number + “ 10”
Feet number + ’ 10’
Millimeters number + mm 10mm
Centimeters number + cm 10cm
Meters number + m 10m

Creating Arrays

An array arranges geometry in a line (linear array) or around a point (radial array). You create an array when you copy geometry with the Move tool or the Rotate tool. The following table outlines all the modifiers you can use when creating arrays.

Array Type How to Specify It Example Spacing
External number + x 3x Equal distance as original and initial copy
External number + * 3* Equal distance as original and initial copy
Internal number + / 3/ Equal distance between original and initial copy

Entering tool-specific measurement values

Immediately after you use a tool, you can enter precise values, which appear in the Measurements box. The values you can enter depend on the tool.

Note: The exact format for a list separator may vary, depending on your computer’s Regional Settings. For European users, the list separator symbol may be a semicolon instead of a comma.

The following links point you to the article that outlines the accepted values and modifiers for each tool:

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