LOD 300 vs LOD 400: which level of detail does your project actually need?

LOD — Level of Development — is one of the most misunderstood acronyms in BIM. Half the industry uses it as a substitute for 'detail', the other half as a substitute for 'accuracy'. The AIA's original definition speaks to neither precisely.

For most coordination work — architecture, structure, MEP federation, clash detection — LOD 350 is the sweet spot. You have enough geometric resolution to clash hard elements and enough information to drive a quantity take-off, without modelling every bracket.

LOD 400 only makes sense when the model is feeding fabrication directly: precast panel layouts, structural steel shop drawings, prefabricated MEP riser modules. The cost of authoring at LOD 400 typically doubles per discipline — only worth it when the contractor or supplier is actually consuming the model.

Our usual recommendation: start at LOD 300 in stage 3, push to LOD 350 for stage 4 coordination, and only escalate specific elements (curtain wall, precast, riser modules) to LOD 400 in the procurement phase.