W7: Scanning Joe (the Cat)

This week we are exploring 3D scanning and reconstruction with limited hardware. We have talked about alternatives applications for photogrammetry, and others based on depth perception. I wanted to use an app that I have used before to scan real-life geometry. It's called display.land because of its interface and social features. It has an editor and animator view where people can create trailers for their scans, and share it with the world.

The scan process takes about 5 minutes of moving around the object. In my scan setup, Joe was sleeping by my window, and I wanted to see if I can finish the scan without waking him up. It worked! He kept sleeping even after my scan returned meshes. You can see a flythrough from the app interface in the above gallery.

I exported the model from display.land as an obj file. The model was decent for a scan, I assume the app processes the point cloud before sending me the final result.

I opened the file with Meshlab for further tweaks. I first removed the extra vertices around Joe. Then, I tried various cleaning operations under Filters -> Cleaning and Repairing. Remove Duplicate Vertices and Remove Duplicate Faces could remove some vertices. After playing with various settings, I found out a couple of holes on the model, Close Holes command worked perfectly and closed the holes.

Then I switched to Rhino/Grasshopper to turn this model into a watertight 3D printable object. I wanted to create a bust-like display. I ended up duplicating the outside edges of the model, extruding it down, and intersecting with a box underneath.

I couldn't manage to apply a boolean union to my objects in Rhino. Despite this, Cura understood the model well enough to produce a printable object. I scaled my object ~40x40x15mm and used a layer height of 0.16mm. The top layers (scanned geometry) requires a great deal of precision. That's why I created a "support box" (translucent box in the figure) in Cura for the scanned geometry and assigned higher precision settings for that section of the print.

The print is coming in shortly.