Programming

Abern26's picture

Titanium

Titanium atom

THis is my introduction. 

enguy18's picture

Nitrogen Atom

Nitrogen
 
Nitrogen is one of the many elements that make up the universe, and it is quite prominent on earth.
Afra's picture

Nitrogen Atom

Nitrogen Atom
It is an element that is an essential to all life on Earth, yet in its purest form it can suffocate living organisms. Nitrogen is one of the most important elements on Earth – it can be found in all living systems and makes up around 78% of the Earth’s atmosphere. It is a constituent of protein and nucleic acids. In its gaseous form, nitrogen is colourless, odourless and generally considered inert. In its liquid form nitrogen is also colourless and odourless, and resembles water. Nitrogen was first recognised in 1772 by number of scientists; Carl Wilhelm Scheele, Daniel Rutherford, Henry Cavendish and Joseph Priestley, who all found that air was composed of three different gases, oxygen, carbon dioxide and another gas which they dubbed ‘foul air’ (nitrogen). Nitrogen was first recognised as an element by Antoine Laurent Lavoiser in 1786, and named nitrogen in 1790 by Antoine Laurent Lavoiser. Today, nitrogen is used in food preservation, explosives, and aids medical research.
Andy's picture

Pokestop

Pokestop

The Pokemon Go App has caused quite a global disturbance since its recent release (date?). Facebook access rate was descresed and more people access Pokemon Go daily than Twitter.  People are busy catching Pokemonsters on the roads, at schools and homes, and in the parks. This short video taken at NYC Central Park shows how popular it is. A search on Twitter for Pokemon go can get a quick understanding of this global phenomenon. Are you playing?

aplesch's picture

X3D: behind-the-scenes

Image ALT text

Here is a look at the 3d technology which drives vrmath behind the scenes. It is called X3D and has its own web site. Understanding this technology not only helps in how vrmath extends turtle graphics into 3d but opens the door to a large world of virtual reality in general (x3dom, web3d). It turns out that the vrmath editor is itself a good tool to get to know X3D. Here is how.

aplesch's picture

more gears, fast

4 gears

I updated the involute (curved teeth), helical gear generation procedure to use Extrusion rather than IndexedFaceSets. Extrusion automatically supports the back and front faces of the gears, and a smooth appearance by producing a mesh with points shared by triangles. So the logo code could be streamlined and therefore is now much faster generating gears.

aplesch's picture

general smoothness

smooth gear

Getting gears to appear smooth by explicitly assigning indices to the generated facets got me thinking in more detail of how to accomplish this result in general, for any facets drawn in face mode by turtle graphics.

aplesch's picture

smoother gears

smoother tooth

Trying to get a smoother appearance for the curved gear teeth involves lessons both in logo programming and in the underlying 3d display technology.

aplesch's picture

involute gear

two gears

It turned out that producing a set of involute gears requires quite a bit of geometry in addition to involutes.