I was involved with a large project. I ended up laser scanning the building in a couple days capturing the building in full 3D using a FARO Focus3D LiDAR. The contractor compared my scans to the Revit BIM model from the architect and realized there was a big problem. The Revit BIM model was created based on measurements taken manually and then all the engineering based on that model which means they were wrong too.
I mean this how we have always done it in the industry. We would send out junior architects and engineers to grab measurements in the early project work and inevitably we would need another dimension and again sometimes multiple times we would send the junior staff out to the project site. It was highly inefficient and not highly accurate when we need all the accuracy we can get.
So in this specific case the people took measurements and missed some and also made some assumptions. Readers, never ever assume one column to column is typical in an old building or old part ever as they are rarely typical or as expected. In this case the windows and columns were mostly wrong in the BIM model and now there was a great deal of re-engineering costing over $100,000 which I am sure that money would be better spent than on mistakes and inefficiencies. Had the original architect simple paid a local expert with a 3D LiDAR laser scanner to scan the building this would not have occurred and saved over $250,000 dollars for everyone.
This is a good (and time consuming and expensive) lesson, and I won’t be pointing out where this was, but I know it happens everywhere and far too frequently in construction. I remember a large airport BIM model with perfectly straight and I scratched my head wondering how 20-40 year old HVAC was so perfect with no sagging or bends. I knew someone probably just grabbed dimensions with a tape or laser measuring tool for the elevations at the begin and end of the run forgetting the point of a model is accuracy to prevent conflicts by other new additions in the remodel. What's the point of building a model if it isn't accurate? Scanning it is always cheaper than the rework and time lost in the project schedule.
https://www.autodesk.com/campaigns/reality-capture
Accuracy is everything
With photo-to-point cloud creation and laser scanning, large scale or small, Reality Capture delivers incredible detail at the outset, preventing costly rework later down the line. Each point captured is mapped onto an XYZ coordinate system, for an intelligent survey output that’s ready to export whenever you need it.
Built-in efficiencies
Starting with a site scan immediately creates a digitized 3D replica that accelerates the surveying and documentation process, significantly reducing labor costs. Reality Capture creates new and efficient workflows, increases productivity, and reduces time and manual effort required.
Less manual work and trips to the jobsite
Armed with digitized data that provides analytical connected insight, surveying specialists can now use their time to point out opportunities or pain points that the design and construction teams may encounter later on instead of spending time doing the tedious manual capture.
Scan it first and save yourself money and frustration.
