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 Making a circle look like a circle
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By: Anonymous: Walt () on Tuesday, December 28 2010 @ 07:03 AM PST (Read 2487 times)  
Anonymous: Walt

I just built my Egg-bot and completed the smiley face tutorial.

However, when drawing it on an egg, the result is an oval, not a circle. Any ideas why?.

Thanks in advance... Walt.

By: Anonymous: bruce shapiro () on Tuesday, December 28 2010 @ 08:59 AM PST  
Anonymous: bruce shapiro

Hi Walt,

Remember that real eggs are not spherical-- they have a long and short axis. The circumference around the long axis is larger, so each step of the pen-motor actually draws a longer segment than a single step drawn by the egg-motor. All this means that when drawing on eggs (as opposed to spheres), if you want your plot to not be elongated in the N/S direction, you need to scale your drawing ~150% in the horizontal direction (depends on the "elongation factor" of your egg), using Inkscape's transformation tools. Also, you'll want to stay near the egg's equator since "polar crunching" is common to both eggs and spheres.

By: Anonymous: Walt () on Tuesday, December 28 2010 @ 09:15 AM PST  
Anonymous: Walt

Thanks for the reply. I thought I was doing something wrong, since the tutorial showed a full sized circle that drew out as a perfect circle on the golf ball. But then again I used an egg. I'll give the tutorial another shot with a golf ball.

Thanks again!



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