4D only works when the programme and the model share a breakdown. Agree it, code both, link by rules, and the sequence keeps working when the model changes.
A 4D model plays the construction programme on the 3D model: each activity makes its elements appear in sequence. Watching it, people spot what a bar chart hides. But 4D is fragile unless the programme and the model are built on the same breakdown, and linked by rules.
The planner splits the job into activities by location and work type. The model has to be split the same way, and its elements have to say where they belong.
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