Define Axis Form

The Define Axis form allows you to specify the motion axis mount point and motion vector. See also Defining Motion Vectors. Whenever a moving body is imported from CAD, the user is automatically prompted to the Define Axis form.

Three options are available for defining the rotation axis and mount point:

  • Surfaces

    User selects a surface of the CAD geometry. The mount point is positioned at the center of this surface and the rotation axis is defined as the unit vector normal to the surface. Hold down the Shift button to select multiple faces when defining the surface. The surface must be planar. The candidate axis is shown in green in the 3D viewing panel. For reference, the corresponding mount point and rotation axis are listed in the form.

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  • Edges

    User selects a closed edge of the CAD geometry. The mount point is positioned at the centroid of the surface defined by the edge. The rotation axis is then defined as the unit vector normal to the surface defined by the edge. Hold down the Shift button to select multiple edges to define a closed loop. All selected edges must occupy the same plane. The candidate axis is shown in green in the 3D viewing panel. For reference, the corresponding mount point and rotation axis are listed in the form.

../../../_images/define-axis-edges.gif
  • Custom

    User manually specifies the mount point and rotation direction. The candidate axis is shown in green in the 3D viewing panel.

Location

The Define Axis form is found on the following context-specific toolbars (accessed through the Create menu):