creating new tracks

creating new tracks  


Joined: 1 month ago
Posts: 1
June 30, 2019 5:55 pm  

I've just gotten my table, and I'm eager to create some new tracks.   Here are a couple of first questions:

1) I can see that thr files are lists of coordinates.  Each line is a pair of numbers "theta r".  I am guessing that theta is the angle in radians and r is the radius (between 0 and 1).  If successive lines in a file read "theta1 r1" and "theta2 r2", what is the *precise* path the table will draw in the sand between the two points?

2) How did people create the default thr files?  My operating system is Linux, so I will not be interested in Mac or Windows tools.  

Any help/advice would be greatly appreciated, and I am looking forward to sharing whatever I create.

Thanks very much,


Joined: 1 year ago
Posts: 42
June 30, 2019 11:20 pm  


The path taken by the ball between points is a linear interpolation in polar coordinates. Which generally means an arc of some kind. So if your intention is a straight line, you'll need to use many points. In my path generation code, I subdivide lines until they are "small enough" (a balance between noticeable and large file sizes). 

The "default" paths ("factory" paths) were all created by artist Bruce Shapiro over the many years he has been making custom Sisyphus tables. The "community" tracks have been made by many folks (including me). Welcome to the group; I look forward to seeing what you make!

All of the outside contributions are using custom code. Some folks have put their code online (e.g., Some just share the results.

Joined: 1 year ago
Posts: 176
July 1, 2019 9:05 am  

@davidp - welcome to the community! Dithermaster is one of our resident experts, and did a nice job describing the thr format, and need for more points when drawing straight lines (analogous to needing more points to draw arc using an XY mechanism). Here is a good starting point for options:

Also, you can take a look at our recent Kickstarter for the Sisyphus Mini - down the page a ways there are links and examples (search for "track composition tools").



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