Metrics for Review Imprint Mode

The surface repair part contact review tool provides you with a set of metrics that gives you an insight into the part contacts contained in the surface.

The metrics are split into two different groups:
  1. Review type metrics - allows you to visualize part contacts and provides details such as the face count, contacting part count, part surface contact count, and contacting area for each part contact part pair.
  2. Diagnostic type metrics - provides a detailed view of the individual part contact topology and allows you to spot issues that would not be obvious from visualization. In general, table values that exceed a certain default threshold value indicate a potential problem and require further inspection.
The table below summarizes each metric and the type of problems it can identify.
Metric Purpose Type of Problems the Metrics can Identify
Part Contact Summary General browse/review tool Contacts containing a small number of faces; higher or lower numbers of part surface contacts than expected.
Contacting Parts Count Review part to part contact relationship Missing contacting parts; parts that should not be contacting.
Part Contact Area Ratio Review contacting area ratio per part Parts that are barely contacting; similar parts that should have the same area ratio.
Contact Area Mismatch Diagnose non-conformal interface (NCI) contacts with area mismatches NCI contacts that have contact area mismatches.
Non-Contiguous Contact Diagnose contacts split into two or more face groups Contacts that contain splits or divides resulting in non-contacting areas.
Non-Contacting Islands Diagnose contacts with non-contacting face islands Contacts that contain embedded non-contacting areas.
Contact Topology Errors Diagnose contacts with critical topology errors Critical surface topology errors relating to the contact (for example, intersections).
Each metric reports the part contact Type in the last column in the table. The Type primarily refers to meshing type contacts and includes the following types:
Part Contact Type Default Selection Behavior
CI Conformal interface
NCI Non-conformal interface
Baffle Baffle interface
Periodic Periodic interface
Weak Weak in-place interface
Empty An empty part contact (has no part surface contacts)
Mixed A combination of two or more of the above types
The Weak type contacts are those created explicitly in the simulation Parts tree (that is, when you right-click on two different part surfaces and select Create Weak In-Place Contact). The Weak type is used when part surface contacts exist in the tree but the current surface description in the repair session does not directly contain these contacts. For example, if you have an imprint operation that creates a new Imprint type description (along with part contact objects in the tree) but you bring the Root surface description into surface repair then the part contacts is reported as having Weak in-place contacts in this case since they are not directly applied to the root surface.

The Mixed type contacts are those that result when two or more different types of part surface contacts are encountered. Instead of listing the individual types, they are reported as belonging to a mixed contact (not to be confused with a mixing type contact in the physics solver). To determine the types making up a mixed contact, use the other tools in repair in conjunction with the Color face by Contact display option.

Part Contact Summary

The Part Contact Summary metric provides a general overview of all the part contacts. Each table entry represents one part contact and lists the two components parts, the total contacting face count, and the part surface contact count, and the part contact types. The image below shows an example of the results for the part contact summary metric:

Along with providing a general method of browsing, selecting and displaying part contacts, the metric can be used to easily identify two specific types of issues that may occur:
  • Part contacts that contain a small or large number of faces
  • Part contacts that contain either too few or too many part surface contacts
If you sort the results based on face count, you can investigate contacts that contain a suspiciously low or high number of faces. For example, a valid conformal or non-conformal interface would typically contain at least 6 or more faces, so any contacts with less than this number of faces should be reviewed.

Contacting Parts Count

The Contacting Parts Count metric provides a summary of the number of contacting parts for each part. Each table entry lists a base part, the parts that are contacting that part, the total number of contacting parts and the contact types for the part. The image below shows an example of a set of results sorted by part count:

By analysing the contacts, you can get an insight into the flow and thermal path from one part to another. This metric is useful for identifying parts that should not be contacting each other.

By sorting the table according to Contact Count, you can analyze the lower values (between 1 and 3) that could indicate unexpected part contacts. These excess contacts are typically produced when an imprint tolerance is too large, resulting in geometry deformation and a thermal/flow path that should not exist.

You can also use this metric for selecting and displaying all the contact faces for a given part using the right-click menus from the table.

Part Contact Area Ratio

The Part Contact Area Ratio metric provides the ratio of the contacting face area to non-contacting face area of a given part. Each table entry contains the base part, the part contact count, the part surface contact count, the contacting area ratio, and the range of contact types for the part. The image below shows an example of a set of results sorted according to the area ratio:

This metric helps you to answer some fundamental engineering type of questions such as:
  1. Which parts have the highest or lowest contacting area?
  2. Which parts have the most part contacts?
  3. Do similar parts have the same contacting area ratio?
  4. Do critical parts satisfy the expected contacting area ratio?
You can sort the table by the ratio value to analyse the parts with the highest or lowest ratio value. Parts that belong to Weak in-place type contacts will always report a 100% ratio value since the entire part is considered to be the contact while in this state. Parts that are entirely immersed or surrounded by another part (for example a box inside a box) would similarly report a ratio value of 100%, hence a value below 100% indicates an issue with the contact.
In the example below, the highlighted rows show four injector tube parts that are identical but where the area ratio is different for two of the four parts. In this case, further investigation found that two of the injector tubes were used in an imprint operation and the tube was deformed due to a large tolerance value.

Contact Area Mismatch

The Contact Area Mismatch metric is primarily focused on diagnosing contact area mismatches for non-conformal (NCI) contacts. Each table entry lists the part surface contact, the base and contacting part, the area mismatch value, and the contact type. The Mismatch value is defined as the ratio of the smallest contact area to the largest contact area for the two part surfaces that comprise the contact.

For perfectly matching NCI's, the areas are the same and the Mismatch value is zero or close to zero. Higher mismatch values, especially those above 5% to 25%, signify some kind of potential issue and should be investigated. Unmatched contact faces can result in incorrect boundary conditions being applied in the vicinity of the contact.

Weak in-place contacts are reported as having a high mismatch % since the part surface faces belonging to the two parts are yet to be matched. Conformal interface (CI) imprints and baffles are reported as having a 0% mismatch, since the faces between the two parts are shared and therefore have identical area.

Non-Contiguous Contact

Contacts can be non-contiguous and contain two or more separate groups of faces. The Non-Contiguous Contact metric evaluates each part surface contact and reports the number of separate face groups making up the contact. For CI type contacts, the minimum reported value is one but for NCI type contacts the minimum value is two since NCI are always composed of at least two separate part surfaces. Each table entry lists the part surface contact, the base and contacting part, the non-contiguous count, and the contact type for the part surface contact.

To identify problems with contacts, you can sort the Count column starting with the highest value entries and then browse through the table results.

Non-Contacting Islands

A non-contacting island is a part surface contact that contains non-contacting faces within the main contact itself. These "islands" can represent both valid situations (for example a plate with drilled holes contacting another plate without holes) and invalid imprints, where one surface has not correctly been projected onto the other surface. This problem is more common in curved surfaces than flat surfaces. These non-contacting faces result in flow obstructions or thermally resistant planes in the volume mesh and produce incorrect analysis results.

Each table entry lists the part surface contact, the base and contacting parts, the non-contacting island count, the area ratio of the non-contacting faces to the contacting faces, and the contact type for the part surface contact. The image below shows an example of a set of results sorted by the non-contacting island count:

The area ratio value is provided alongside the island count so that you can assess if the non-contacting faces are dominating the definition of the part contact. A low value could signify that the issue can be ignored or given a low priority for inspection. For non-contacting islands within NCI contacts, the non-contacting area is calculated for faces on both part surfaces, resulting in a higher than expected value. A large non-contacting island count does not necessarily mean that there is a problem with the contact.

Contact Topology Errors

The Contact Topology Errors metric summarizes the topology surface diagnostic results (pierced faces/edges, free edges, and non-manifold edges) for each part surface contact. In order for this metric to be available, you must enable and execute at least one of the topology diagnostics in surface repair. Each table entry lists the part surface contact, the pierced faces count, pierced edges count, free edges count, non-manifold edges count, and the contact type.

NCI type contacts are composed of two part surfaces so a high pierced face and edge count is expected for this type of contact. If a topology diagnostic is not enabled when the metric is calculated then the column entry shows "Disabled" for that diagnostic result. Re-enabling and executing the diagnostic flags the metric results as out of date.

Since all topology errors are considered critical errors, any reported error value greater than 0 must be investigated. The metric helps prioritize which contacts have the most errors and therefore should be looked at first.

The default Row selection behavior option for this metric selects the problematic faces and edges for each table entry, allowing quick highlighting of the problem areas while viewing the contact parts in some other color mode (such as color faces by Contact or Part). This metric has particular uses for detecting multiple intersections when imprinting thin parts.