New York Skyline

By November 8, 2013News

This summer we were fortunate enough to work in the Big Apple, right in the heart of it all, at the New York Metropolitan Museum of Art.

We were commissioned to scan the base structural components of a large skylight on one of the buildings that houses an Asian cultural exhibit.  The scan was to be completed in a very tight window of time due to service providers are only permitted on site during specific hours on a single day of the week.

Maneuvering through TSA and flying into LaGuardia airport with all of that scan equipment was a challenge, but not nearly as challenging as driving to the site through mid-town Manhattan during morning rush hour traffic in a rental car – that is an experience I’ll not soon forget (at least the rental was a Chevy Impala SS which made me suitably equipped for competition).  Note to self: New York does have a few taxis available, if needed.  Lesson learned.

Every job provides its own unique challenges and this was no exception.  The skylight to be scanned was seated on a 5 foot base of concrete block which meant that its base was high compared to the surrounding vertical surfaces – this made it difficult to set targets dispersed in a manner the would yield good geometric control for the subject.

Also, the entire roof area surrounding the structure was blanketed in a temporary 2×4 plank catwalk-type floor that, although well constructed, had suffered from the elements and would shift under any weight.  This made it difficult to ensure the instrument was level and while scanning we needed to stand very still to not disturb the scan head.

To address both of these challenges, we used a set of lightweight carbon-graphite camera legs (that’s survey talk for tripod) that allows for some unique setup configurations.  Using them, we were able to set up on the structure itself with just about an 18 inch ledge to support two of the legs with the third resting on the skylight itself.

Another approach used to guarantee we were scanning everything needed by the client was to set the scanner up on parts of the building adjacent to our subject with higher elevations.  There is a certain sense of unease that accompanies the action of porting a 50 pound box filled with what is the equivalent of a few years salary up and down a shaky ladder on the roof of a building.

All joking aside, the most important aspect of this project was to capture the steel structural components that the skylight was seated on; the original glass and its frame is to be removed from the structural steel and a new frame will be pre-fabricated to precisely fit the structural steel that is to remain.

As there was a masterfully crafted replica of an ancient Asian village courtyard inside the building just beneath our work area, workers had to carefully remove corner sections of glass as well as a section between two opposite corners to expose the steel.  This was slow and tedious work, but once the glass panels were removed the structural components to be scanned were adequately revealed.

After the scanning was completed for the day, the raw scan data was reviewed on site with the client to make sure we were capturing everything to their satisfaction – returning to this job site to pick up something missed would be an expensive error.

After returning to Truescan3D Headquarters in West Chester, Ohio, the raw data was post processed and the scans were combined into a singular point cloud.

After delivering the data to our client and their initial review of it in Autodesk Inventor, they requested to have the structural components modeled in 3D so that they could use the models to design the new skylight frame without needing to interpret the cloud data on their own.  Having trained eyes for these things, this was something we were able to provide for them with relative ease.  In the end, they were able to complete their work with the models provided and we look forward to working with them on future projects.

This was an interesting and fun job, and a challenge not only technically, but also in that it was a ‘quick hitter’; although we had been discussing the possibility with the client for months, it came to life very quickly, over a couple of days, and suddenly we were on a plane and off to the most incredible city in the world – New York, the ‘Big Apple’, or after my dinner that evening after the scan I now like to affectionately refer to it as the ‘Big Slice’ (link).