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Levels of High Definitions Scans

by Cindy on January 27, 2014

The request for proposals for high definition laser scanning is increasing on construction and renovation sites.  The one thing I am unfortunately noticing is the inconsistency with the level of scan that is being requested verses what is actually needed.  It is hard to write a request for proposal when there is the possibility that the firms bidding on the projects are using different scanning equipment and each set of equipment has different settings for the quality level and range.  So when trying to compare each firm’s proposal you are not comparing “apples to apples”.  There are a couple of things you can do to ensure you are able to compare “apples to apples”.
 
I would say 90 percent of the work we do for laser scanning projects is on a medium level of scan; however, a low level scan might be requested for initial BIM work or rough models for preliminary design and a high level scan can be used for ornate objects, detailed cornices or architectural features.  Instead of asking or requesting a low, medium, or high level of scan, provide a detailed scope with what the scan data is being used for and what accuracy needs to be achieved with the scan data.  For example different scanners have the same settings of low, medium, and high levels; however, at a medium setting one scanner picks up 122,000 points per second where another scanner picks up only 50,000 points per second.
 
Another item I am seeing requested is how many scans to complete a project.  Since each scanner is different, picks up a different number of points per second, and have different ranges, the number of scans per project will differ.  Also, the amount of time a scanner takes to collect the data is different.  So, unless each firm that is bidding on the project is using the same equipment these items will not be comparable. 
 
The main key for bidding on a project is making sure the end result is usable to the client.  There are many different scanners on the market that can achieve the same goal, but cannot be compared based upon the level of scan or number of setups.  I would suggest asking the vender what equipment they are using and how they plan to achieve the accuracy and collect the data required for the project.