We had the pleasure of scanning a clay model of a cave that is going in a museum. For scale, this model was made to equal one inch for every foot. They needed a full to scale model of it to figure out how to construct and quote the HVAC and fire sprinkler system.
We approach each job differently and this one was going to prove difficult just due to the nature of it. The only parts that could come apart were the roof sections. All other parts were affixed into place and could not be removed. SO it had to sit as-is to be scanned. Our hand held Artec scanners were too big to fit down inside the model to use for scanning. Also, in the process of photogrammetry, a DSLR would also be too large to fit inside the structure for scanning. So there we were scratching our heads thinking how to capture this when I realized, “Hey, we have a GoPro we can use!” We had to light the model from above with two large LED panels to illuminate the inside of the cave and I placed a flexible array of LED lights down on the walk path of the cave model to help add more light shining up into the model. Now, when scanning things we typically like to scan objects we can look at from the outside….something like a tree for example. You take images of an object to construct the 3d data and “if” you had to do it in sections it would be easy to align and put together! Not this thing! We have to scan the inside of this object as well as the outside and would be pure Hell to align all the different parts if we chose to scan in sections. So the approach was to do it ALL at ONCE with no stopping….PERIOD! We set the GoPro on time-lapse to take a shot (12mp image) every second. Once I began I knew I had to just keep going until I felt I had enough coverage of the interior and exterior. The motions from spot to spot were very small increments and you have to also take into account that some of those shots will have motion blur and be un-usable.
So after digging into the processing part we had 4,641 images to go through….piece of cake, right!? Most of the images were ok due to having adequate light for the camera. Slight tweaks here and there in the darks/lights. And away we went into the Photogrammetry software! Lets just say it took a minute! lol
For fun I placed the model in an environment and added some simple materials to it!