Creating shells that screw into each other
Since my last post about this, the code is improved to read arbitrary (convex and concave) polygons and convert them into screws (and various other improvements). This program directly generates GCode, the result does not need to go through a slicer first.
Each screw is printed as a spiral vase in a continuous shell which makes it strong and creates a flawless surface. The results are really fun to play with!
Find the code on github:
Ok, that is really fun.
I want to go play with this right now. Sadly I am working. This week!
@Henner_Zeller
Could you consider using your experience and skills on the DNA playlist on thingiverse, that originally came from the NIH website?
The DNA parts are suppose to fit together but many people have difficulty getting the right slicer settings.
Could you do the same thing for the DNA STL files?
That would help schools and teachers to be able to print them to use in the classroom.
If the STL is a general shape, then you have to go through the slicer as it can prepare any general shape to a printable GCode file, @Richard_Turnock . In this particular example, these are specialized shapes that can be translated to GCode directly - but that is only a small subset of all shapes.
If things are simple shells, slicers should be able to make it a continuous vase-print as well (at least I know slic3r does), but that is indeed a setting the user has to make. Unfortunately slicers are not good enough yet to output the best GCode for any general purpose shape without human interaction 
The DNA models seem to be more intricate and couldn’t be made a simple shell print. There, indeed, difficult settings have to be done to have parts fit together properly as that depends on the machine (accuracy, but also nozzle-diameter, printing material, temperature) - a lot of trial and error. However, it should be possible to distribute the slicer settings to other schools that use the same printer.
Yes all good
Thank you
Containers for CNC endmills are often shaped like this, so they can handle different bit lengths.
For that use case, I now only need to add a closed-side feature to keep them inside, @Daniel_Joyce 
Very nice. under what licence is that published ?
That is (cc) BY-SA, @Dominik_Wenger . I should probably switch to some license that is more commonly used for software, such as BSD, but (cc) is it for now .
