Posts in category Week 5

(Smart) prototyping

As the final working week begins, we must decide what precisely our explorations in production methods will lead to. In the beginning of the project our supervisor Maaike said that the priority and goal of the project was to “revive” chosen historical objects. She did not specify how leaving us to decide what it is supposed to be. As seen in the first post, we took the task very directly, thinking that filling the holes in different methods will bring the most successful results. After four weeks it is clear that archaeological ceramics can not only regain their original use, but also become a game or a party attribute. Therefore, it is essential that we decide how these ideas can be smartly introduced to our peers and supervisors: interaction and functionality being the first priorities.

To begin with, we would like to introduce the cup as a relatively cheap party attribute. Last week we strove for two solutions: paper printing and vacuum forming. Only the latter could come into life, but as it is, the cup could be called a high fidelity prototype for cold beverages containment.

Secondly, the cup as an interactive object. The idea behind this is rather simple: providing the user with a kit consisting of cup shards and color-able glue, both child-safe and heat resistant. Interpretation of the objects would vary with the user: it could be interpreted as a DIY project, treasure hunt for children or possibly an exercise object for amateur archaeologists. For the presentation we will have the shards and the glued cup ready for the exposition, making it again a high fidelity prototype.

Another idea, consisting of two solutions, is to restore the original function of the cup. The first silver bullet was to underline the cracks by making them in different material. In the end we decided on rubber, which gives a rather pleasant feeling for the cup bu making it partially flexible. The second solution is at least 70% rubber, which makes the flexibility a problem. Due to that, an inner structure is introduced, making it possible to implement very interesting spacial compositions. The latter cannot be fully explored before the end of the project, but a simplified version will be given to explain the main idea. In other words, during the science fair we will present the structure prints instead of two material prints: the cost of rapid prototyping in 2 materials is too high for research models. As for the first idea, the design is almost complete and therefore these costs can be justified.

Hope to see you in the science fair on the 27th of October, 12:00 in the faculty of Industrial Design Engineering, TU Delft, Stevinweg 1, 2628 CN Delft.

Revision of scan results

As promised, we would give the summarized results for the two scanning sessions that we had: with CT scanners and with Artec Spider scanner.

Part of the results of the latter unexpectedly disappeared during the post-processing. The scan which promised the most for us, Hermione handle detail, was among the missing files. We hoped to get better results of the floral ornament and combine it with the CT-scan body, only the chosen comparison model and Harry survived.

Kam artec spider

As seen, for the comparison we chose the finest model we had. The lice-comb teeth were approximately 0.5 mm diameter with even smaller gaps between them. Due to this, the scanning technique used by Artec Spider could never achieve a proper result: too much was not visible, even with the precision of 0,05 mm. In other words, the grid which the range finding device projected could not be interpreted in the gaps and the result was a block with a texture instead of a comb. Moreover, looking at he scan of Harry we can see a big inconvenience for us: only the outer surface and the sections at the breaks were captured. Moreover, the cracked surface texture was not captured, because we got the file only in a mesh file.

artec scanner harry

Therefore, it would be expected that this problem would not be so apparent in CT-scans. This technique captures the sections of the object, instead of making an interpretation of surface. Just then these sections are interpreted into 3D files. However, the precision of 0,3 mm proved to be insufficient for the artifact we chose:

macro CT kam

As seen, the result was a more consistent file, which could actually be printed. Nevertheless, it was far from what we would call sufficient. Expecting this, we also made micro-CT scans of the object. The sneak-peaks of the object in the lab itself looked very promising. Yet our and publicly available computers could not handle the size of the data set (over 2000 sections!) and could only give results in the lowest resolution, leaving us with the following model:

micro kam

As seen in the picture, the separate teeth are clearly visible, although the main body is missing. This can be easily solved if the used computer has 16GB RAM, since we could get a proper model in Avizo a few moments before it crashed due to memory insufficiency.

To conclude, only the micro-CT scanner offered the sufficient results for the compared artifact. The Artec Spider is very interesting if surface detailing in necessary or if textures/colors have to be captured. However, if not enough scans are made and combined, you will get an object lacking details, thus resulting in incredible amount of work hours in post-processing. Another solution for this would be to make CT-scans and combine them with the Artec Spider scans only for the details.

© 2011 TU Delft