DWG to BIM: what to retain and what to review
A DWG can contain valuable geometric information, but it also carries the history of the drawing process. Old alternatives, detached references and inconsistent layers can make a seemingly complete file ambiguous. Preparing it for BIM means separating reliable design information from drafting residue and stating which conventions the new model should follow.
Keep the evidence that matters
Retain dimensions, grid references, level information and annotations that explain the architectural intent. Include any linked drawing files needed to interpret the package. Review the source in its intended context rather than sending an isolated plan with essential backgrounds missing. Identify the units and a dependable reference dimension. If several alternatives occupy the same file, identify the chosen proposal explicitly; location on the screen is not a sufficient status label for someone outside the practice.
Review before simplifying
Look for duplicated geometry, obsolete details and text referring to superseded drawings. Work on a copy when preparing a cleaner package so the practice keeps the original record. Avoid removing information simply because it looks untidy: a small note may explain a wall thickness or a change in level. Where linework conflicts with a written dimension, state which information governs or log the discrepancy. The conversion should not quietly turn a drafting inconsistency into a modeling decision.
Agree how the model will be structured
Discuss levels, architectural categories, element names and the expected treatment of repeated components. Explain which existing office standards must be retained and which are only CAD conventions. A layer name can inform the brief without determining the final model structure. Agree the output format and any Revit version requirement before starting. A preliminary check of one representative area can reveal problems with coordinates, scale or interpretation before the whole building is modeled.
Before handing over a DWG
- Open the prepared package with its necessary references and confirm that the selected design alternative is clearly identified for the external team.
- Record known unit, dimension or source inconsistencies in the brief so the modeler can raise them without rediscovering their project history.
- Check a representative modeled area against the approved drawing hierarchy before permitting repeated geometry or assumptions to spread across the building.
Send the DWG package with an index, current revisions and a short list of known limitations. Add sections and elevations when the plan alone cannot explain the geometry. At review, compare the model with the approved references and the decision log. Keeping the reliable information is more important than preserving every line, layer or drafting habit in the original file.
Sources and technical reading
General guidance: each project's scope is confirmed before commissioning.