In order to make a monkey saddle I created the surface in Mathematica. I then exported it as a .wrl file and imported it into Cinema 4D. Once it was in Cinema 4D, like all surfaces, I made it the correct size, optimized the polygons and extruded them by 0.20 cm.

I then added an equation to the surface by punching it all the way through. This time with the equation I used Arial as the font instead of Times New Roman to hopefully avoid the issues we had with the formula when printing the hyperbolic paraboloid.

I printed the monkey saddle using the liquid printer and the formula in Arial font ended up looking great. The model can be found on Thingiverse here

# Helicoids

My next project (after finally finishing all the quadratic surfaces) was to make a helicoid. I spend some time on Mathematica creating different helicoids by changing the parameters of the formula. The helicoid is pararametrized by $$x=u\cos(t), y=u\sin(t),$$ and $$z=u$$, where $$u\in[-1,1]$$ and $$t\in[0,2\pi]$$.

Professor Denne and I decided to print two of the ones I created to start (we may print more!). I exported the following Mathematica files and imported them into Cinema 4D.

Professor Denne used these files (as well as others) to create another worksheet in Mathematica. It can be found here

After making them the correct size I optimized the polygons and extruded them by 0.20 cm (a process I can now do very quickly after all my practice with the quadratic surfaces). I then printed each of them on the liquid printer and had fantastic results!

The .STL and .form files for both of these helicoids can be found on Thingiverse.

Later on, I made another helicoid, this one with $$u\in[0.25,1.25]$$ and $$t\in[0,2\pi]$$. This model can be found on Thingiverse here.

# Klein Bottle

Just a really short post to share our general excitement over having just about completed all of the objects from Multivariable Calculus. We just have a few more to print out. We will spend our remaining week(!) printing out some interesting topological objects – many of these directly from Thingiverse.

We printed one such object today. This is the Voronoi Klein Bottle from MadOverlord on Thingiverse. We printed this on the MakerBot 2X with a raft but no supports. After a moment’s thought one can see that the print succeeds (despite the short horizontal lines on the design) because the Voronoi cells are small enough. Interesting! The black filament also hides a few rough spots on the print.

The Klein bottle is named after Felix Klein (25 April 1849 – 22 June 1925), a German mathematician who saw many connections between Group Theory and Geometry. It is a one-sided surface and is a generalization of a Mobius strip. (In fact, it is topologically equivalent to two Mobius strips glued together along their boundaries.)

There are many fabulous descriptions of this topological object, one of my favorites is The Adventures of the Klein Bottle found on YouTube (from the wonderful folks at the Frei Universitat in Berlin).