Fredrik Stenström

Background facts: The original metallic subway sign was first made in 1933 by the artist Kalle Loden. It was updated in the 1950´s to its current form as a lit up transparent plastic ball design. As the sign is probably molded by hand there was no proper drawings for the sign I got the mission to carry out accurate and detailed digital drawings for future reference. So I really had nothing to start with except a life size version in our clients office.

Since I had no references or drawings I had to figure out the best way to make an accurate 3D model so I tried out 3 different methods: 1. Photogrammetry which is a quick way of adding multiple photos in different angles of an object and then generating a base mesh in software. Unfortunaltely this technique cant handle shiny or transparent objects so while the room turned out great the sign and lamp post didnt stick. 2. LIDAR which is a method of laerscanning objects and then create a mesh from the resulting point cloud. The result came out good but we used outdoor long distance scanners and the accuracy was not enough since we needed closer range to catch all the details.

3. So in the end I decided that classic manual measuring by hand were the best method to use in order to get the accuracy needed. The object may seem easy to model but there are a lot of arcs and angles that really dont match up correctly since the original mold is made by hand and contain discrepancies between the 3 sides.

I then modelled the sign based on parametric modeling methods to reatian an as good approximation of the real life object as possible.

Final drawings delivered together with 3D CAD-model. And when I was ready I thought I would add a bonus so I decided to...

...3D print the modell and create a desktop lamp as a bonus delivery and surprise my client.

Said and done first testprint came out pretty good. A lot of testing to print such thin parts to get it transparent and at the same save as much printtime as possible without having to create to much support structures.

The "T" character was glued to the base model to complete the first third of the lamp.

I testprinted with quite high layer height (0.3mm) to speed up the print process thats why the layer lines are so visible in this test print. But it saves a lot of time.

I added a quite rough modeled connector for the lamp post but since its not visible to the eye I figured it was good enough. It actually turned out a perfect fit on first try. Sometimes you are lucky :)

Comparison between the original subway sign and the 3d printed model (scale 1:5). Can you tell the difference? ...of course you can ;)

Final lamp as a guiding light at the office :)