When performing conflict detection, you may sometimes encounter multiple conflict results for each individual layer of a wall or floor. This usually means that your multilayered element (e.g., a wall or floor) was exported with each layer represented as a separate IFC element part.
Why this happens
In IFC-based workflows, especially when exporting from tools like Revit or Archicad, multilayered components can be broken down into individual parts. While this can be useful for quantity takeoffs or detailed modeling, it can cause issues during clash detection, resulting in redundant or excessive clash reports, one for each layer.
Why simply unchecking "Include Parts" doesn't work
Unchecking the "Include parts" in conflict detection option will not always solve the issue. The reason for this can be found in how the IFC file is exported.
In some cases, exclude all parts from detection will not have any result, because the parent element is composed solely of those parts. It removes the parts from the clash check, but there is no overall parent element left to check.
In other words, disabling parts in the conflict detection tool doesn’t give you one result per wall but it gives you no result at all.
The solution
To avoid getting clash results per layer and instead have one result per whole element, you need to ensure your IFC export does not break elements into parts in the first place. Below is how to handle this in both Revit and Archicad:
Revit
Default Behavior: Walls and floors are exported as single, solid elements.
To ensure parts are not exported, in your 3D view’s properties, set “Parts Visibility” to “Show Original” instead of “Show Parts.”
Result: The wall or floor is exported as a single IFC element, with no separate layers or parts included.
Archicad
Default Behavior: Multilayered elements (like composite walls) are displayed and exported with visible layers.
To export as a unified element, in the IFC Translator settings, under “Material preservation mode,” select “Never Explode elements.”
Result: The wall or floor is still visually layered in the model, but behaves as a single element in the IFC. You can’t select layers individually (e.g., with Shift+Click), and only one clash will be reported for the entire element.