About Creating Half Dimensions

Half dimensions are useful in the case of revolved features or elements using a plane symmetry, as they let you create the dimensions only on half the geometry.

This topic provides more information about half dimensions.

This page discusses:

See Also
Creating Half Dimensions

Half Dimension

  • You can create a half dimension directly by selecting first an axis line and then another element (which is not an axis). The half dimension value is the double of the measured value between the elements.
  • Once you select the half dimension option from the context menu, it is stored as a preference and all the subsequent dimensions you create will be assigned the half dimension mode. This behavior is applicable for both dimensioning cases (from an axis to a geometry and from a geometry to an axis).
  • If you do not want a half dimension to be created or if you want to create dimensions in the standard mode, clear the Half Dimension option from the context menu when creating the dimension.
  • When using Stacked Dimensions, the first dimension created (half or standard) decides the type of the dimension of the system. Dimensions created subsequently in the system have the same type as the first one.

About Dimension Value and Associativity

  • The dimension value is doubled when they are made out of two selections (distance, angle, 2D diameter cylinder, radius cylinder) but not for dimensions made out of one selection (angle on cone, 3D diameter cylinder, diameter edge, diameter tangent).
  • Associativity in the case of half dimensions is different from associativity in the case of standard dimensions. For example, the half distance dimension below is associated with the axis and the element, whereas a standard dimension is associated with both symmetrical elements.
    Standard distance dimension:
    Half distance dimension:
    Diameter and radius dimensions are usually created with one selection in 3D. If the dimension is created with two selections, for example an edge coming from a 3D revolution and another element, the dimension is not associative. To create the dimension below, you must select only the left or the right side of the cylinder and then right-click the dimension and select Half Dimension.
    Half diameter dimension: