BIM fundamentals

Building — the subject. Information — each element carries data: type, dimensions, materials, fire rating, cost, manufacturer. Modelling (or model, or management) — the process of creating and sharing that information. A BIM model is a structured database you can see in 3D.

Every Revit element has parameters — named values. A door has Width, Height, Frame Material, Fire Rating, Mark. Some belong to the type (every 820 × 2040 door) and some to the instance (this particular door's mark and sill level).

You can schedule, tag, filter and colour elements by any parameter. That's what makes a door schedule or a fire-rating plan automatic.

Elements know about each other: doors are hosted in walls, walls are constrained to levels, floors are bounded by walls, rooms are bounded by walls and floors. Change a level's height and every wall constrained to it adjusts. These relationships save time — and explain some surprises, like a wall moving because a level moved.

A floor plan in Revit is not a drawing — it's a horizontal cut through the model with display settings. A section is a vertical cut. Deleting a view deletes nothing from the building; deleting a wall removes it from every view. Annotation (dimensions, tags, text) belongs to a single view.

On real projects, architects, engineers and contractors each produce models, which are combined (federated) to check coordination and clashes. Standards such as ISO 19650 describe how that information is requested, produced, named and shared. The KitWren BIM course covers this in detail.