Christmas updates

Ho ho ho!

Well, thank you all for your support this year, hope you’re not regretting it!

Software updates:

  • New straight lines.  I have improved C17, the “draw straight line” command.  This now works!  More or less.  There’s still a subtle curve to some lines, with some orientations being more pronounced than others.  This works by splitting the line into lots of little bits, and so although close up they’ll look a little wiggly, overall they should be straight.  And certainly a lot straighter than the old “fastest move” method.  The button for this is “move direct”.  The number of sub-lines it gets chopped into is controlled with “<” and “>” (max segment length).
  • Speedometer.  The motor speed and acceleration speed are both now specified as absolute values rather than relative ones.  The current speed and acceleration is shown in the info overlay, and the keyboard controls are the same, that is “*” and “/” to change the acceleration, and “+” and “-” to change the max speed.
  • Values of motor speed, acceleration and pen tip width are preloaded into the queue on start up.  This should keep things in sync better.
  • Command queue line drawing preview.  This is a little thing, but hints at the next big thing for polargraph machines – vector graphics.  Andy Kinsman has done some brilliant work on writing a little PostScript interpreter that will convert PostScript vector graphics output into line commands for the Polargraph.  This is the best thing that’s happened to polargraphs since ever.  He has a wiki page on the code site and I haven’t had a chance to play with it properly, but hope to get into it over the holidays. It’s very exciting.  So if you load a queue full of C17 commands into the controller, you’ll have a little display of what it might look like drawn.  It’s primitive so far, but this is just the beginnings.
To get the straight lines working, I found a problem with my mmPerRev settings.  Which means all you probably have that problem too, you should fix it.
Set machine.motors.mmPerRev=95.0 to get better fidelity.  It shouldn’t make much difference, but the old setting of 84 is one bead too short, and will lead to your images being compressed vertically, and maybe distorted with narrow bottoms.  Give it a shot please, sorry about the mistake.
There are also a couple of new properties that get saved in the config file, so do a “save” to rebuild your file.
Let me know how you get on, and have a merry christmas and a happy new year!

2 thoughts on “Christmas updates

  1. *Grinning*

    Yesterday I was wondering if vector line art would ever be possible with a polargraph, and now news that it’s in the works! I was thinking it would be fun to print out pieces for large papercraft sculptures that my “normal” (wee) printer couldn’t handle. Improved straight line printing would help with that, too.

    Since I self-sourced my roller blind cord, I measured it carefully, and got 95mm over and over and wondered where I was going wrong, then just entered “95” and hoped it would work. Guess I should’ve mentioned it earlier.

    • You were best to ignore my advice I think – I noticed that the bead pitch of the new was slightly different to the old cord so I _was_ looking for a new, lower value. But when I re-measured I just did it wrong, and didn’t think twice about why it was so different. I am very susceptible to off-by-one errors it seems! The straight lines still aren’t completely straight, especially at some angles, so aren’t up to what you’ll need for plans and things, but I think I’ll get it fixed eventually – it’s a float/integer rounding thing, so I hope just needs a slightly reformulated algorithm.

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