BIM clash detection is the process that identifies potential errors in the federated BIM model, allowing them to be solved during the design phase before construction process has even begun.
In BIM modeling there's not only one model, but different models for each discipline (structural, plant, energy, etc.)
Once the various AEC professionals, each for their own specific discipline, have finished their part of the design and systems sizing process, the resulting models are merged into a single federated 3D model in which it is possible to identify any conflicts before construction. And this is where BIM clash detection comes into the scene.
The main purpose of BIM clash detection is to identify the specific points where different models can overlap. Detection of BIM interference is an essential part of the BIM workflow and ensures that there are no problems in the model that may affect project delivery or costs.