Tuesday, October 18, 2016

Virtual steality - take your own Disney Treasures - Me-Gifting - AKA out of word play

It's not that I don't appreciate the fine merchandise in the souvenir store at Disneyland Park. It's just that Duffy, Itchy and the Gang are not for me. So if I am to leave Disneyland Paris with a tchotchke that I can appreciate, I am going to have to be creative. Enter Agisoft.

Ignoring the mournful gaze of the Phantom Manor cast member (or was it mere pity?) I began photographing the plaque outside the queue entrance. By taking a few dozen shots with a Sony A7S2, I was able to rebuild my would-be souvenir as a 3D model in Metashape using the magic of photogrammetry. Unfortunately this was not good enough for my pointlessly high standards. The spiky teeth of the freaky head guy were missing from this reconstruction.

According to the Agisoft manual, taking around one hundred pictures of this checkerboard would enable the software to compute a more precise model of my camera's lens distortions, and make a better model.

Fortunately a kindly Imagineer took pity upon me and pointed out that the checkerboard cannot have the same pattern if it is rotated 180°, so I had to 'shop out the last row of squares from each photo. OpenCV Brownian Distortion lens model algorithms are at play here.

Upon feeding the calibration into Metashape...
He's still gamming at me! Next I tried bumping up the Clarity in Photoshop in an attempt to create more localized contrast for Agisoft to key on when the focus is not perfect. This also sometimes helps with photos that don't align properly. Then, I tried super-sampling the images before doing any tweaks.

I was quickly coming to the conclusion that my efforts to make my souvenir had failed. Perhaps the Sony did not have gift-shop quality resolution, or perhaps the photos were taken at too wide of an angle (35mm) to be useful.


With only one option left, I bit the bullet and purchased a Sony 90mm macro lens, a linear polarizer to block reflections, and airplane tickets back to Paris. This was now the most expensive souvenir ever. *A kindly mouse may have helped with the ticket cost.

155 photos later, we have pointy teeth! Now it is just a simple hopelessly complicated matter to place the data in a 3D printer and push the "Should have just bought the Duffy" command. Would that it were so easy. The Agisoft export has holes and no thickness, so some further processing is needed. I turned to DesignX to do some more robust manipulations than Metashape currently provides.

Note to self: don't be afraid to brush away spider-webs, they had a visible impact on the quality of the Crypt Keeper's right side.

The penultimate step is to bring the design into a program called Geomagic Sculpt, which is the cleanest method of voxelizing 3d printer data to ensure water-tight meshes and manifold geo. It is also a good place to smooth out any rough patches and refine the model in an intuitive sculptural manner. This is because one can feel the 3D model using Sculpt's haptic feedback stylus. Here's another heisted souvenir in Sculpt:

Ready to print using Photoshop CC, our go-to support generation software for extruded filament printers.


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