# Message #1898

From: Roice Nelson <roice3@gmail.com>

Subject: Re: [MC4D] Re: yet more new puzzles and a prize

Date: Sun, 06 Nov 2011 18:42:58 -0600

No worries at all - I had just wanted to let you know rotation was

available.

It looks like Don has hardcoded the motion model (which he did

independently of the hyperbolic geometry model), and not provided a key

toggle to switch it. My apologies for not mentioning that earlier. To see

the other models, you’d need to recompile his applet after altering the

code. In the version I have downloaded, the code is around line 1374 of

the file HyperbolicApplet.prejava file, and looks like this:

```
//int motionModel = TRACKBALL;<br>
//int motionModel = DRAG_GEODESIC;<br>
//int motionModel = DRAG_NONPRECESSING;<br>
int motionModel = DRAG_PURETRANSLATE_CLAMPED;
```

You could change what is commented to try the other models. Getting a

setup to recompile would probably take some effort though.

With regards to hyperbolic geometry models, I’ve played with a few of these

in MagicTile, but I haven’t yet made the controls work for them. I just

uploaded a couple pictures… some puzzles in the Klein model, and one

pasted on the pseudosphere <http://en.wikipedia.org/wiki/Pseudosphere>.

The Klein model may become my favorite view when solving puzzles. It has

a very spherical feel to it, due to circles getting squashed towards the

edges, and magnifies pieces near the center. I don’t think the

pseudosphere ends up being a very workable view, since you can’t show a

large percentage of the hyperbolic plane on it at once.

http://groups.yahoo.com/group/4D_Cubing/photos/album/1694853720/pic/list

seeya,

Roice

On Sat, Nov 5, 2011 at 4:38 PM, schuma <mananself@gmail.com> wrote:

> Sorry for not noticing the middle mouse drag function.

>

> In Don’s applet I don’t know how to change to another motion model.

> Poincare model/Klein model behave in the same way. I’m not surprised by

> anti-procession because rolling a ball is anti-procession. Since sphere and

> hyperbolic plane are opposite, it’s natural to see procession in the

> hyperbolic plane. But I don’t know how to see anti-procession in hyperbolic.

>

> Nan

>

> — In 4D_Cubing@yahoogroups.com, Roice Nelson <roice3@…> wrote:

> >

> > Middle-mouse drag will do a rotation for you (or on a laptop, left+right

> > drag at the same time).

> >

> > I find the noncommutative panning in spherical/hyperbolic spaces really

> > neat too (doesn’t happen for Euclidean space, so middle-mouse control is

> > required there). The code for Don’s hyperbolic tesselations

> > applet<http://www.plunk.org/~hatch/HyperbolicApplet/>was super helpful

> > in understanding and implementing this. Internally, you

> > can see he played with a few different motion models, some of which

> > anti-precess rather than precess! That is, dragging clockwise results

> in a

> > counterclockwise rotation of the space. I found that I liked the one he

> > settled on for his applet the best too, though it’d be nice to add in

> some

> > of the others as an option.

> >

> > seeya,

> > Roice

>