Short answer:<\/strong> Revit authors the model and produces the sheets. Its Interference Check compares geometry inside the model and its links. It does not review the issued PDF set, and it cannot see a discipline that was never modelled \u2014 which on most projects is several of them.<\/p>\n This is a question about scope, not quality. Revit is the authoring environment for a large share of design work in the United States. The gap below is what happens between the model and the set that actually gets built.<\/p>\n Interference Check reports where elements in a Revit model, or in models linked into it, occupy the same space. Run during authoring it catches a duct through a beam while the duct is still cheap to move. It belongs in the workflow and nothing here suggests otherwise.<\/p>\n Its boundary is the model. An element that was never modelled cannot interfere with anything, and a requirement that lives in the specifications is not geometry at all. So the check answers one question well \u2014 does this collide with that \u2014 and is silent on the rest of what a coordinated set has to get right.<\/p>\n Architectural and structural are usually modelled. Mechanical and electrical sometimes are. Plumbing, fire protection, fire alarm, low-voltage, telecom, civil, landscape, interior design, food service, signage and the specifications frequently are not \u2014 they are drawn, issued as PDFs, and coordinated by someone reading them.<\/p>\n That matters because coordination conflicts do not distribute evenly. They concentrate at the seams between disciplines, and the seams involving the un-modelled trades are exactly the ones no model-based check ever examines. A project can pass Interference Check cleanly and still carry a fire alarm device in a location the ceiling plan does not allow.<\/p>\n Contract documents are drawings and specifications. The model is a means of producing them. When a sheet and the model disagree, the sheet governs \u2014 and sheets acquire changes the model does not always receive, through addenda, bulletins, ASIs and RFI responses issued under deadline.<\/p>\n So the document that has to be internally consistent is the issued set, and the issued set is what nobody checks comprehensively. Rework on building projects runs 4.6% of contract value, measured across 32 buildings in a 2009 study of 359 projects. Design error and omission alone accounts for 1.5% of contract value within that total.<\/span> On a $40 million job, that 1.5% is roughly $600,000 of field rework traceable to the documents.<\/p>\n Those are third-party research figures, not ours. Each is traced to its primary document in our construction rework statistics register<\/a>.<\/p>\n They operate at different moments on different artifacts. Interference Check runs inside the authoring environment while geometry is being decided. A plan review<\/a> runs on the issued set, after the drawings exist, across every discipline in the submission including the ones that were never modelled \u2014 and it reads the specifications as part of the set rather than as a separate document nobody cross-checks.<\/p>\n Using both is not redundant. One keeps the model honest; the other keeps the set honest.<\/p>\n Flikt.AI reads the whole submission rather than sampling it: every sheet against every other sheet, drawings against specifications, across all 16 disciplines at once. It reports spatial conflicts, specification-versus-drawing mismatches, missing coordination where something required is absent from the sheet it belongs on, and clearance issues where drawn dimensions leave less room than the referenced requirement needs. The five kinds of finding are set out here<\/a>, and where this is not the right tool<\/a> is published just as plainly.<\/p>\n Send the 2D PDF drawing set you already have, exported from Revit or assembled from consultant issues, and the specifications if the project carries them. Findings come back tied to the sheets they came from. For the model-based comparison in more detail, see clash detection without a BIM model<\/a> and reviewing a set without Navisworks<\/a>.<\/p>\n Revit reports interferences between elements inside a model, including linked models, using Interference Check. That is useful while the model is being authored. It does not review the PDF sheet set that was issued, and it cannot see a discipline that was never modelled. On most projects several disciplines arrive as drawings only.<\/p>\n No. The review runs on the 2D PDF drawing set, which is the form the project is issued and built in. There is no model to build, nothing to federate, and no modelling staff required.<\/p>\n Anything that is not geometry in the model. That includes specification requirements that contradict the drawings, a note on one sheet that disagrees with a detail on another, a schedule that does not match what is drawn, a required element missing from the sheet it belongs on, and every discipline delivered as a PDF rather than a model.<\/p>\n It is the common case rather than the exception. Architectural and structural are frequently modelled while mechanical, electrical, plumbing, fire protection, fire alarm and low-voltage arrive as drawings. Those disciplines are where a large share of coordination conflicts live, which is why a model-only check leaves the harder half of the problem untouched.<\/p>\n Yes. Sheets exported to PDF from Revit are ordinary drawings, and they are reviewed the same way any issued set is: every sheet against every other sheet, and the drawings against the specifications.<\/p>\n
\nWhat Interference Check does, and where it stops<\/h2>\n
The disciplines that never make it into the model<\/h2>\n
The set that gets built is the PDF, not the model<\/h2>\n
How a plan review fits alongside Revit<\/h2>\n
What Flikt.AI checks<\/h2>\n
What you send<\/h2>\n
Frequently asked questions<\/h2>\n
Can Revit check my drawings for coordination conflicts?<\/h3>\n
Do I need a Revit model to get a plan review?<\/h3>\n
What does Interference Check miss?<\/h3>\n
Our architect models in Revit but the engineers do not. Is that unusual?<\/h3>\n
Can the drawings exported from Revit be reviewed?<\/h3>\n