Tutorial 9: Creating Measures for stretching models

Last modified: Sep 17, 2019
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In this tutorial we are using examples to explain how to make a static 3D model parametric by creating what we refer to as Measures.


  • Before you start defining measures, you need to make sure that LODs and 2D are built as building LODs and 2D after creating measures will break the stretching behavior.


  • Download the file KC.cmsym by following the link.
  • In Model Lab, open KC.cmsym by using File->Open (or simply by dragging and dropping the file onto Model Lab).
  • Verify that the model is shown in the 3D view and locate the Stretch section on the left side of the window.


  • Click the blue plus sign to start an animation for placing a new measure.
  • When the cursor enters the 3D-view, a green marker and a grid around the selected node are shown.
    • If no node is selected, a grid around the entire model is shown.
  • Note the grid resolution in the user interface. This can be changed prior to starting the animation or while animating by using the arrow up/down keys.
  • The green marker snaps to cross-sections in the grid, so changing the resolution of the grid could be helpful when placing the end points of the measure.
  • Left-click to attach the start point of the measure.


  • Move the cursor and left-click again to attach the end point of the measure.


  • Next, we are dividing the measure into different sections. In the image above, we have two sections. Sections are useful for controlling how different parts of the model change when the length of the measure is changed (i.e. when the model is stretched).
  • Note the help points in the 3D view. The number of help points can be changed prior to starting the animation, or while animating, by using the arrow up/down keys.
  • The green marker will snap to the help points which are placed along the measure.
  • We click twice to divide the model into three sections.


  • Note that there are some changes to the user interface in the Stretch section.
  • The measure currently has the default name “measure1”. This can be changed by clicking the “Set ID” button. In our example, we change the name to “width”.


  • Next, let’s look at the Sections user interface.
  • These settings are used to control how each defined section is changing when the length of the measure is being changed.
    • You may change the length of the measure by:
      1. Changing the Length slider.
      2. Entering a new value in the input field to the right of the “Length” slider.
      3. Dragging the measure start/end point markers (yellow and orange respectively) in the 3D view.
  • In the image below, the length of the measure has been increased.
    • Note that the middle section remains the same size since we have set it to 0%.


  • All sections should always add up to a 100%; otherwise the model will not change according to the measure length change.
  • Note that you can decide if you want the model data associated with a section to “Scale” or “Move”. You may want to use Scale if you want a surface to preserve a rounded shape while being stretched.
  • Use “Reset” to reset the length of the measure.
  • Use “Swap points” to swap the start and end points. This may be useful if the using application has decided to always stretch from, for instance, the end point of the measure.
  • Save the model to a .cmsym file.
  • Congratulations! You have just converted a static 3D-model to a parametric 3D-model.
  • You may also test the model by dragging and dropping it onto CET Designer.
  • You can create multiple measure for a single model, as in this example:


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