Configuring A Hard Clash Test | Help

A Hard Clash test detects physical intersections or elements separated by less than a defined minimum distance.

In a standard Hard Clash test, Selection A is checked against Selection B. You can also enable Internal clash (same model) to check for clashes between elements within a single selection.

Before you start

Before configuring a Hard Clash test:

Create or open a Clash Test with Hard Clash selected as the Clash Test type.
Make sure the required models are available in the selected Coordination Space.
Identify which groups of elements you want to compare.

For information about creating a Clash Test, see Creating a Clash Test.

Defining Selection A and Selection B

By default, a Hard Clash test compares two groups of elements:

Selection A defines the first group of elements.
Selection B defines the second group of elements.

For example, to check whether ducts intersect structural beams:

Use Selection A to select the ducts.
Use Selection B to select the structural beams.

Each selection can use the models available in the Coordination Space and can be further restricted to the elements you want to analyze.

You can also add multiple selection sources to the same selection when the elements you want to include require different criteria.

For detailed information about selecting models, adding conditions, and combining selection criteria, see Selecting elements for a Clash Test.

Using Internal clash

Enable Internal clash (same model) when you want to detect clashes between elements within a single selection instead of comparing Selection A against Selection B.

When Internal clash is enabled, Selection A and Selection B are replaced by a single Selection.

For example, you can use Internal clash to check for intersections between elements within a selected group of ducts.

Disable Internal clash when you want to return to a comparison between Selection A and Selection B.

Setting the Minimum Distance

Use Minimum Distance to define the minimum separation required between the selected elements.

Set Minimum Distance to 0 when only physical intersections should be detected.
Enter a value greater than 0 when elements should also be detected if the distance between them is below the specified minimum.

For example, if you set the Minimum Distance to 50 mm, elements can be detected when they intersect or when the separation between them is less than 50 mm.

Use a value that reflects the clearance required for your coordination objective.

Ignoring clashes within the same system

Under Advanced settings, enable Ignore clashes between elements in the same system when clashes between elements belonging to the same system should not be included in the results.

This can help reduce unnecessary results when coordinating systems whose elements are expected to connect or interact with each other.

Leave this option disabled when clashes between elements in the same system are relevant to your coordination check.

Previewing the selections

Preview each selection before saving the Clash Test to confirm that the correct elements are included.

For a standard Hard Clash test, you can preview Selection A and Selection B separately. When using Internal clash, preview the single Selection instead.

The preview helps you:

Confirm the selected elements visually in the viewer.
Check the number of elements included in the selection.
Identify selection criteria that are too broad or too restrictive.

BIMWorkplace also checks the total number of selected elements against the limit allowed for a Clash Test. If the limit is exceeded, reduce the scope of the selections or split the check into multiple Clash Tests.

For more information about building and previewing selections, see Selecting elements for a Clash Test.

Saving the configuration

Before saving a standard Hard Clash test, make sure both Selection A and Selection B are configured.

When Internal clash (same model) is enabled, configure the single Selection instead.

Also review the Minimum Distance and Advanced settings to make sure they match the purpose of the test.

Save the Clash Test when the configuration is complete.

Example: Ducts vs. structural beams

Suppose you want to identify ducts that intersect structural beams.

Configure the Hard Clash test as follows:

Selection A: HVAC model – Condition: Ducts.
Selection B: Structural model – Condition: Beams.
Minimum Distance: 0 mm.
Internal clash (same model): Disabled.

With this configuration, the test checks the selected ducts against the selected structural beams and detects physical intersections between them.

If the coordination requirement also specifies a minimum separation between ducts and beams, enter that value in Minimum Distance instead of 0 mm.

After saving the configuration, run the Clash Test from the Clash Tests page and review the detected clashes in Clash Results.

Creating a Clash Test
Selecting elements for a Clash Test
Configuring a Soft Clash Test
Configuring a Duplicate Test
Clash Tests
Clash Results