Sunday, August 30, 2009

SketchUp - Changing Dimensions

SketchUp is a nice free program from Google for 3D modeling. It is very intuitive, easy to use for the most of it, however there are still some not that obvious operations like, for example, changing dimensions of different shapes to exact value.

The fist what should be said is that SketchUp model is not driven by dimensions which are setup by "Dimension" tool - those dimensions are just text and arrow objects, so one can click the text and change it to any other text not even related to any dimension. Furthermore, in most cases you really do not want to modify them this way - such a change will kill the possibility of the dimension value to track the true size.

The unpleasant thing about changing dimensions is that it should be done different way for different shapes:
  1. For a line segment - right click on it and choose "Entity Info"

    Type a new value in the "Length" field, hit "Enter" and that will make the change.

  2. For 2D shapes - select a 2D face with "Scale" tool

    then select a green box which corresponds to the dimension you are intending to change


    The "Red Scale" field ("red" indicates that the scaling is along the red coordinate axis) in the right bottom corner of the SketchUp window by default is in scale mode. Just type a new exact dimension with a unit (1m in this example)


    and press "Enter" - the dimension will change and the value will follow.

  3. For 3D shapes (mostly the same as for 2D case) - with "Select" tool select a whole shape

    switch to "Scale" tool

    and select a green box corresponding to the dimension you're going to change.


    Type a new exact dimension with a unit (1m in this example)


    and press "Enter" - the dimension will get changed.
For more complicated shapes it is easier to create a reference at required position and then modify the shape with "Move", Push/Pull", "Scale" or other tools to align with the reference. A simple line segment, a guide line or a guide point (created with "Tape Measure" or "Protractor") can serve as such a reference.

2 comments:

Anonymous said...

I want to re-due my back yard but the dimentions are too big for the screen. How do I size them down to fit?

SVN said...

If you’re talking about scaling the image of your yard to see it all in SketchUp window – there is Zoom tool which you can find in menu/Camera/Zoom (or just press ‘Z’); to fit it at once - menu/Camera/Zoom Extents (shortcut is Cntrl+Shift+’E’); in any other mode zooming can be adjusted by mouse wheel. At least that’s how it is in Windows I use, Mac version of SketchUp may have it slightly different.

Size of the dimension value itself, if this is the case, can be adjusted too - right click а dimension with Select tool and choose Entity Info, then Change Font to a smaller one. Also it is possible to change units and precision of measurement: it’s in menu/Model Info/Units.
I hope it helps.

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