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A model with more detail is not automatically a better model. Every extra element takes time to build, check and keep up to date, so the real question is what the model has to support.
What LOD actually describes
Level of development describes how much geometry and information an element carries, and how far the design team can rely on it. At LOD 200 elements are generic placeholders with approximate size and position. At LOD 300 they have their real size, shape, location and orientation, so you can measure from them and draw sheets from them.
When LOD 200 is enough
- Massing and feasibility. Testing options, areas and heights before the design settles.
- Early coordination. Reserving space for plant rooms, risers and main routes.
- Quick existing models. A light model to set out a small extension.
When you need LOD 300
Choose LOD 300 when drawings will be issued from the model, when other consultants will coordinate against it, or when quantities matter. Wall build-ups, door and window types, structural sizes and main service routes are modeled as they will be built.
How to specify it in a brief
Name the LOD per discipline and per element group rather than for the whole model. A short table, for example walls and openings at 300, furniture at 200, keeps the scope clear and the price honest.
Conclusion
Match the model to the decisions it supports. Start lighter where you can, go to LOD 300 where drawings, coordination or quantities depend on it, and write it down before modeling starts.
