3D Model Construction Site

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1

Hi,

I am looking for some help please. I have been asked to make a 3D model of a construction site (including cranes, buildings, scaffolding, diggers, etc). I did the survey as per appropriate instructions and then flew manually along the side of the buildings to get images so that it would reduce the melted effect.

The client wants to upload the .obj files into REVIT so they can view through VR Goggles.

When I sent them the files (this was just a test run) they did not want ANY melted scenes. Clearly, there is a lot going on at a construction site so I was looking for the following info/help please:

  1. Once I have done the initial scan (from the pre-programmed flight path in the app), how many photos should I get of each side of each building? Should I get these at different heights too so there are numerous angles?

  2. Should I also photograph (with the drone) all of the on site equipment such as the trucks, lorries, diggers etc?

  3. What is the maximum amount of photos we can use to import into the software for editing?

  4. Can the 3D Model be done over 4 overlaying areas to increase quality?

Any help or advice would be hugely appreciated.

Thanks,

Sam Pile
Perspective Media Ltd
Director
sam.pile@perspective-media.co.uk
+44 7515 379 554

2

Hi Sam! First question is does the client understand what they are asking for? Have they seen a 3D model generated from drone data before? I ask this because their expectation may be unrealistic. A lot of times when you get with contractors that are used to looking at 3D scans in Revit they are looking at lidar scans and terrestrial laser scanners. An expectation needs to be had that there is no way to create a perfect 3D model via photogrammetry. That being said you can make a pretty darn good run at it.
First you need to look at what types of objects are on the site. Buildings during construction can be hard to model because of the lack of consistent surfaces, but I should not be too hard to get and may require some special attention. Scaffolding is pretty much a lost cause and many times can distort other parts of the model by trying to get special imagery for them. Cranes are something that are very hard to model well and will take a dedicated flight of their own.
I would suggest trying to fly either during lunch or on a day that they are not working like the weekend. This will cut down on moving targets and help create a better static 3D model. Start with a crosshatch at 60 degrees and 250 ft, followed by another crosshatch at 50 degrees and 220 ft. You can run a little lower if you like, but these aren’t the tubes are usually pretty good about keeping away from things like cranes and tall structures on construction sites. Lastly, I would identify the highest value targets and do an orbital scan of each one. If the cranes are really tall he may need to do to orbital scans at different altitudes. It’s going to be a lot of pictures, but that’s what it’s going to take to get close to the quality that I think they are anticipating. On an example 30-acre site I would guess this would be around 2000-3000 photos.