Friday, August 06, 2021

Untergroeningen Station Building (2)

[ part 1 ]

I've constructed the station building shown in part 1 in Tinkercad, which is a very easy to use online 3D CAD tool. I know it mostly as a tool for users that want to send the resulting model to a 3D printer. Tinkercad makes exact sizing of the model very easy. Measurements of elements are readily accessible, and changing values is trivial.

Developing a 3D model from photos and drawings is interesting. Especially the roof geometry remained a challenge, though at last I finally figured out what the geometry actually must have looked like, based on how the roof lines develop from the walls and what I can deduce from photos taken at eye level from the ground. 

I didn't want to 3D-print the station building, but rather wanted to build a paper model. Much more economical than springing for a 3D-printer and filament. There are many instructions and tools to unwrap 3D models. Dedicated payware like Pepakura (Windows only), Unwrap3D, plugins to Blender, or the native UV Editor built into Blender. I found that unwrapping the whole building became very cumbersome, so I exported only the roof structure as STL from Tinkercad, imported that to Blender, manually set seams using the UV Editor, and constructed a sensible unwrapped roof. Exporting the unwrapped roof from the 2D view in Blender leads to a very low-resolution PNG. I took a screenshoot instead, scaled it to the right dimensions in GIMP, and printed it. Not high-quality, but more than sufficient to cut the shapes. Since the walls are basic boxes I just measured and cut lengths of card stock in the right dimensions.

The photo above shows my first attempt of the paper building on the Untergroeningen module. While the walls look properly proportioned in the 3D model on screen, the paper model is a bit too plump, or fat, when comparing to prototype photos. The roof seems to be a bit too flat as well. The next version is going to have slightly higher walls, and a slightly steeper roof. Adding 3mm to each story and the roof should do the trick.

When comparing with a freight car on the tracks, the building sits too low as well. I need to raise the ground a few millimeters and have a proper building foundation.

Otherwise, I'm pleased with how this scene is developing.

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