Introduction: TfCD 3d Scanned Wrist: Custom 3d Printed Watch

Interest was found in the application of home 3D scanning and printing. People are able to create a custom product with these technologies. Wrist scanning is the focus of this assignment.

3 technologies combined to create form fit products: Personal 3D Scanning - pictures need to be taken in the dark on an iPad: Trimensional Transfer and processing via an application - process pictures with algorithm into model - app 3D printing - the model is send to an (Ultimaker) 3D printer or a company that prints it more professionally that also delivers the watch to put inside.

Practical Application In alternative technologies can be read that the price range of 3D- scanners and printers is very broad. Because the goal for the team is to make 3D scanning and printing accessible to anyone, the focus is on the applications made based on the camera of the electronic mobile devices instead of an add on product. The app Trimensional was bought for 0,99€. This app is checked for possible applications it can be used for. For trials the faces were scanned, after this a wrist. These scans give an inside in the reach and accuracy of the back-end processing of the app.

Research question Can the outcome scans of the app be used for accurate measurements to calculate dimensions of a wrist?

Step 1: 3d Scanning

Scanning

The team locked themselves in a dark room with an iPad to make several wrist and face scans. The room needed to be perfectly dark and the iPad needs to be around 20 cm away from the object. The screen needs to be on full brightness.

The picture below shows what the app does, in the timeslot of 2 seconds, the 4 parts of the screen light up to show the difference in depth. An effect that occurred was the deformation of the complete face: (insert picture) the deformation was clearly different if we used the app on the Iphone or on the Ipad. The difference in distance between the center of the screen and the camera provides a different view of the object. Assumably it would be optimal to have the camera in the centre of the screen but that has not been seen in any device yet. The team created an watch wrist band that can be 3D printed but without the measurements taken from the scan. They measured the size of the wrists by hand and used this in the CAD program SolidWorks to be able to print it. In the future they would like to use either perfect scans and algorithms for the wrists to be measured or an algorithm working with grasshopper, that can be made into a parametric system.

Step 2: Analyzing Results

The strongest points of the trimensional app are the price and the ease in usability, the app is installed for $1, the download takes less than 10 seconds, a dark environment is all it takes. The scans are not great but but sufficient for the price we paid. The team did a lot of experimenting with different surroundings and settings, but even with the perfect conditions, the scans are not accurate enough to use as reference data. Another problem is that there is no proper scaling, the model can be warped or distorted.

The scans can be made with an angle of 180 degrees. It therefore needs to pictures of an object to make a complete 3D model of it. The app needs to be able to circle around the object, using a point-cloud of geometric values that will be connected to reconstruct the shape. This app only takes 4 pictures while professional 3D scanners take at least a hundred to be accurate. The recommendation for further development of this app would be to increase the amount of pictures and create a stronger reference system in order to have a precise registration.

Step 3: 3d Printing

The model we see over here was 3d printed around the housing of an old watch, the measurements were inserted in a solidworks file, that was exported to STL and inserted in a ultimaker 3d printer.

To make the design of the watch a bit more outstanding, the sides were colored afterwards.

Step 4: Conclusions

3D scanning.

A 3D scanner developed for the iPhone works by shining light onto an object from different angles. The images it shoots are processed in an algorithm to interpret it to create a 3D model. This app called Trimensional is working solely with the camera of the iPhone or iPad itself. This app costs €0,99. There is also a company called Cubify that created a mini scanner that can be attached to the back of an iPhone or iPad that makes 3D scans and connects it to a 3D printer. The scanner alone is €257. Professional 3D scanners that are used for medical and research purposes cost from €1500 up till and over €50.000. Depending on the purpose it is used for the scanners are chosen. For medical reasons a 3D scanner needs to be very accurate and precise with measuring. 3D printing. In the future the techniques of 3D printing and 3D scanning will keep growing, it is also becoming more affordable for normal users. 3 years ago, the cheapest 3D printers costed at least €1000 now the cheapest ones can be ordered for €300. Also the quality is growing extremely rapidly, multiple materials, colours, hardnesses and even transparent materials are no problem for the latest 3d scanners. The most expensive ones go up till 1.000.000€.

The fact that within the last couple of years the price of 3D printers and scanners dropped already incredibly shows that the accessibility for the common people to use it is getting better. Also the quality is improving looking at camera technologies. It is already possible to capture images in 4K resolution, giving an extreme high quality. Adding this quality into an burst of pictures when these scans are brought into a reference system means the quality of the model will increase a lot. The app scanner however is definitely not accurate enough yet to be able to measure the dimension and shape of a wrist.

Expected in the future is that the technology software and hardware of electronic mobile devices will develop even faster and better, making it a very plausible future prospect to easily print any watch desired.

Sources:
3D scanner app for iPhone and iPad Trimensional: http://www.trimensional.com/ Cubify 3D scanner for iPad: http://cubify.com/products/isense Professional 3D scanners: http://3d-scanners.ireviews.com/2014-best-3d-scanners-under-50000-review

Step 5: Examples

The scanned objects can be used to model new shapes around, for example the scan of a wrist could be the input for an automatic generated precisely fitting watch. Below a set of 3D printed legs is seen, the remaining part of the body was 3D scanned and in the computer, the prosthesis was adapted to fit the body.

The same goes for these broken arms, they were 3D scanned and the casting was 3D printed. A precise fit is required for medical reasons.

Comments

author
DIY Hacks and How Tos (author)2015-12-17

3D scanning is probably the best way to get perfectly fitting accessories.

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