MBD Rules and Notes

General

  • Location tolerances always require a dimension, otherwise there will be a warning. The same applies to symmetry.

Examples of warnings

  • Location tolerance, basic element and dimension:

  • Symmetry warning:

Non-MBD features utilizing MBD functions

Error colors:

  • By default, validation errors are represented by colors in both the model and the model tree.

  • When you hover over a markup in the model or tree, a tip appears that includes errors and/or warnings.

  • By default, errors are colored red and warnings are colored orange. However, these colors can be changed in the system settings:

Element restrictions

  • In annotation input instructions, you cannot select layers.
  • The following geometric tolerances are invalid for specific surface shapes:
    • Plane

      1. circularity

      2. cylindricity

      3. concentricity

      Cylinder

      1. flatness

      2. symmetry

      Sphere

      1. straightness

      2. flatness

      3. cylindricity

      4. parallelism

      5. perpendicularity

      6. angularity

      7. symmetry

      8. total runout

      Spline surface

      1. All shapes

    • Otherwise all except the following are disabled (e.g. torus, or spline surface):

      1. Profile of line

      2. Profile of surface

      • This makes it impossible to e.g. model a very large spherical surface and say that it is a plane within a tolerance.

Error checking rules

Check 1: Datum exists

  • Checks that the datums assigned to the geometric tolerance exist.

  • Enabled for all geometric tolerances that have datums assigned.

Check 2: Datum assigned

  • Checks that at least one datum has been assigned to the geometric tolerance.

  • Enabled for all orientation tolerances: parallelism, perpendicularity and angularity.

Check 3: Parallelism

  • Checks that the datum normal is parallel with the mbd element normal.

  • Enabled for parallelism geometric tolerance.

Check 4: Perpendicularity

  • Checks that the datum normal is perpendicular to the mbd element normal.

  • Enabled for perpendicularity geometric tolerance.

Check 5: Concentricity

  • Checks that all of the datums are of valid shape for concentricity.

  • Checks that the datum center axis is aligned with the center axis of the mbd elements.

  • Enabled for centric geometric tolerances.

Note: A single rule can cause multiple warnings/errors, but only the first of a single rule is visualized at a time, i.e. the first error stops the validation rule. For example, a concentricity rule checks both the shape of the datum and the parallelism of the datum axis with the element axis.

Input checks

Duplicate datums

Duplicate datums on a single element are not allowed directly or indirectly. Adding a datum to e.g. a geometric tolerance acts the same as adding a datum to the surface the geometric tolerance is connected to. The program gives an error in such cases.