General Information
Measurements, independently of their type, have a few things in common.
About Measurements | |||||
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About Measurement Accuracy
The accuracy of a measurement depends on the accuracy of the underlying geometry (that is, the geometry upon which the measurement is based).
Understanding How Accuracy Works
- 3D Accuracy (Sag)
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The value used to tessellate geometrical data is known 3D accuracy, or sag.
3D accuracy influences the quality of the 3D geometry, and may therefore also influence the accuracy of a measurement.
- Exact Geometry vs. Approximate Geometry
- Exact geometry contains canonical information (line, circle, plane, cylinder, cone, and sphere), whereas approximate geometry does not contain any canonical information.
- Measurement Accuracy
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The accuracy of a measurement depends on the 3D accuracy, or on the sag, of the underlying geometry.
If the result is exact, the accuracy value is 0.001mm. If the result is approximate, the accuracy value is twice the sag value.
What You Should Remember
- A measurement is exact only when all selected geometries are exact. If at least one of the selected geometries is approximate, then the measurement is approximate.
- Once the measurement is created, you can display the accuracy mode by
selecting the measurement and clicking Display More
in the context toolbar.
The Specific Case of Measurements Based on Section Curves
When you cut through objects using a section plane, section curves are displayed. When creating measurements based on section curves, you need to keep a few things in mind.
- Section curves are considered as approximate geometries. Therefore, measurements based on section curves are approximate.
- Measurement based on section curves are not associative. If you move the section plane, section curves are modified, but measurements are not modified accordingly.
- You can only create measurements on section curves, not on the cut area enclosed by the section curve.