Validate your assembly

The assembly validation checks the correctness of your model based on various criteria:

  • Free parts (parts with no connections and no boundary conditions)
  • Disconnected model regions (groups of parts that have no connections between them, though the parts in a single group are interconnected)
  • Unmeshed parts (parts that you forgot to mesh or for which the meshing failed)
  • Assemblies without connections (assemblies with more than one part inside, but no connections at all)
  • Misplaced contacts (contact surfaces with large distance between them)
  • Parts with wrong number of connections. Available only for parts from the StandardComponents and SpecialComponents library. These parts are validated against the expected minimal and maximal number of connections allowed. E.g. a motor is expected to have exactly two connections (one with the shaft, one with the flange)
  • Multibody parts without connections. Parts that consists of more than one volume body are called multibody. The validation expects that a multibody part will have at least one internal connection.
  • Missing boundary conditions
  • Outdated parts (parts that need to be generated, since upstream dependencies, e.g. CAD files, were changed)
  • Wrong bolted contacts. All contacts involved by bolts are expected to be of type “Friction contact”. Bolted contacts of other types will issue warnings. Bolts with the option dummy=1 are not considered in this validation type.
  • Missing loads-free loadsteps. Some models require that one or more load steps are free of loads. This is the case for example if your FE assembly contains bolts, which must apply pretension in their own load step, while all other loads are applied after that.

Follow the next steps to perform an assembly validation:

  1. In the model tree, select the assembly you want to validate. This is typically the main assembly, but you can also validate a sub-assembly.
  2. In the details area, click on the button "Validate":
  3. In the validation window, click again on the symbol

If any issues are found, corresponding or related model tree items are listed in the separated tabs of the validation window. Select those items and take actions to fix the issues. See these tips on how to handle the validation warnings. After fixing the issues in one cathegory, refresh the validation of other tab with warnings.

How to handle validation warnings

Free parts

  1. Check the positions of the free parts relative to neighbor parts.
  2. Is the position correct?
  3. Is the gap or penetration larger as expected?
  4. Is the contact finding tolerance to low?
  5. Is the option "Use only nodal sets when available" in the "Generate connections" frame set? If Yes, check if free parts contain nodal sets but not on required surfaces.
  6. In case of curved surfaces, is the mesh fine enough to capture the real curvature?
  7. If appropriate, define the connection manually and then use the function "Apply contact offset" in the contact properties.

Disconnected model regions

  1. The typical checks are similar to the point above.

Empty parts

  1. Select an empty part in the model tree and click on "Debug STEP" in the details frame.
    The 3D model of the STEP file will open in a new window.
    If only some of the surfaces are visible, then these surfaces could not be meshed.
    If possible open the STEP file with your CAD software, simplify some features, save it again as STEP and click "Generate" to remesh.
  2. Select an empty part in the model tree, right click on it and select "Open output file" from the context menu.
    Search the file for errors and check the number of volumes. If the parts consists of no volumes and a shell thickness is not set, meshing will abort.

Empty connections items

  1. Check the assembly containing an empty connections item.
    If the parts inside this assembly should have connections, then perform the checks listed under Free parts

Misplaced connection items

  1. Select a connection item that is missplaced.
    If connected surfaces are wrong, click on "Choose other geometry" in the details frame.
    Select the correct surfaces.
  2. Select a connection item that is missplaced.
    Examine if the connection has areas in contact and other areas with large geometrical penetration.
    In some cases large geometrical penetration can cause convergence problems so take actions to restrict the contact area to avoid these effects.
  3. Select a connection item that is missplaced.
    If none of the above points is true, then recomputing the contact offset should solve the validation warning.
    Simply click on "Apply contact ofsset" in the details frame.

Parts with wrong number of connections

  1. Select the part that issues the warning
  2. Right click on it and choose "Show dependencies".
    The new window will list available Connections, Positionings and LBCs.
  3. Examine the available connections. The part wil have either more or less connections than required.
    Either suppress wrong connections or add missing connections.

Missing boundary conditions

  1. See Define loads and boundary conditions

Outdated parts

  1. Select the assembly containing the outdated parts
    The parts will be re-generated.

Wrong bolted contacts

  1. Select the items that issue the warnings.
  2. In the details area click on "Friction contact".
    This will change the contact behavior to "Standard" and set a default friction coefficient.

Missing loads-free loadsteps

  1. Select the LBC items that represent external loads such as forces.
  2. In the details frame expand the area "Loads step editor".
  3. Edit the starting points of the loads to e.g. 0.5 seconds.
    This will create a loads free load step at time point 0 seconds.


  1. Select the different materials listed.
    In the model tree, all parts of same material are selected.
  2. Check if the material assignment is as you woul expect.
    If not, select single or multiple parts, change the material parameter and click "Generate"