TutorialsInferred Dimensions Introduction
Inferred dimensions are driving dimensions that are created automatically when you use such built-in SketchUp tools as Rectangle or Push/Pull. Inferred dimensions capture your design intent and convert it into a set of driving dimensions put on the geometric entities you have just created.
For example, if you draw a rectangle and then move one of its vertices, your face will not preserve its initial rectangular form. So you can lose the initial design intent when moving something in your model. Driving dimensions help you to preserve the form: if you add angular dimensions to your rectangle (one angle equal to 90 degree between two adjacent edges and two other angles equal to 0 degree between two pairs of opposite edges), then it will keep its rectangular form after moving any of its vertices (you can always choose between manual or automatic update of your geometry to satisfy a given set of driving dimensions).
To learn the inferred dimensions, we propose you to follow step by step this simple tutorial aimed at designing a sample house model.
First, open the Options dialog by pressing the rightmost button on the Driving Dimensions toolbar:
The Options dialog will appear:
Please be sure that «Generate Inferred Dimensions» and «Update Geometry After Editing Driving Dimensions» checkboxes are checked, and «After editing geometry...» radio button is switched to «Do nothing» (as on the picture above).
Now start designing the house with a rectangular face on the ground. Select the Rectangle tool from the Drawing toolbar:
...and draw a rectangle:
As you can see on the picture above, some driving dimensions have been added automatically to your model: two lengths and three angles. You can edit their values right now or later at any level of design, and your geometric elements will be automatically updated to satisfy the new values.
To set the desired length of your house, select Driving Dimension tool (by pressing the leftmost button on the Driving Dimensions toolbar):
...and double click on the text area of one of the length dimensions. The following input box will appear:
Type in desired value (e.g. 15’) and press OK button. Your model will be updated automatically:
Now select the Push/Pull tool by pressing the corresponding button on the Edit toolbar:
...and pull the rectangle up:
You can see (as on the above picture) that six more driving dimensions have been automatically added to your model: 4 angles with value 90.0 degree, one angle with value 0 degree, and one edge length. These driving dimensions will help you to keep the design intent inferred by the Pull operation: the vertical corner edges of your house should be orthogonal to the ground face, while upper and bottom faces should be parallel. The length value of the vertical edge can be used at any time to change the height of your house. We will change it later.
Now continue with creation a roof. For this select the Line tool:
... connect the midpoints of two opposite edges of the upper face:
...and move the new edge up (along the blue direction) with the Move/Copy tool:
Your result should now look like on the picture below:
Note that one of the angular dimensions has been highlighted in red. It is an indication for you that the geometry of your model does not satisfy this dimension. Indeed, your bottom and upper faces are not parallel anymore, so the angle between them differs from 0 degree. To update the values of violated («red») driving dimensions, select the «Update values» command on the Driving Dimensions toolbar:
Now your model should look like this (with updated value for the angle marked in green):
You can edit this value by specifying the desired angle with Driving Dimension tool (to access the text area of the corresponding driving dimension label you will probably need to zoom in your model):
Our house does not look so beautiful since it is not symmetric. To make it beautiful, add the same angle on the right part of the house. For this, select the Driving Dimension tool, click on the right part of the roof, then on the right wall and input the same value (45 degree) in the appeared input box. If it is still not symmetric, draw a horizontal line on the façade connecting two upper corners and add the angle dimension between this line and the bottom façade line:
Look at the house from different points of view. If you find some non-symmetric situation, just add more driving angles between the elements. You can also add doors, windows, apply materials to your house.
If driving dimensions label do not allow you to see the details of your house, you can hide them temporarily by pressing the Hide button on the Driving Dimensions toolbar:
To unhide your driving dimensions, press the button again.
Please note that your house is completely parametric — you can change its width, length, height, roof angle, window and door size without breaking your design intent. For example, if you change the height of the house (with Driving Dimension tool), the door and window will remain unchanged, as well as the roof:
Driving dimensions entities (both added manually or generated automatically with the inferred dimensions functionality) are stored with your model, so you can share your house via 3D Warehouse or other 3D modeling user communities. And anyone who installed the Driving Dimensions plugin can easily modify the dimension of your house for his/her needs.
Have any question on this tutorial? Please don’t hesitate to put them in Driving Dimensions User forum at http://DrivingDimensions.com/forum or address us by e-mail: sketchup@DrivingDimensions.com.
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