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Jason Dorie
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I love children, but I can't eat a whole one.
I love children, but I can't eat a whole one.

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Does Smoothie do accumulation of relative GCode moves in fixed precision (IE, the gcode values as large integers simply without a decimal) or float precision (as in, the gcode values after they've been converted to float)?

I'm generating GCode output for an image plot as all relative moves, as multiples of 0.1mm, and the image slowly leans to the right. If I run the same GCode through a back-plotter it comes out as a perfect rectangle.

The only thing I can think of is that 0.1 is a repeating binary decimal, so accumulating in float space over time would lose bits, whereas accumulating in integer before converting to float wouldn't have that problem.

Thoughts? I can post the GCode if anyone wants to try it for themselves. It's almost entirely X-relative G1 moves with S- commands for laser power.

I noticed in the smoothie source that the minimum number of axis has to be 3. For a laser, is there a reason it couldn't be 2? Would reducing the number of actuators reduce processing time for the block queue?

Are there notes anywhere about the most compact form of GCode that Smoothie accepts? Specifically I'm looking for:

- Is it legal to omit the leading zero before a decimal?
- Are spaces required between codes (the Wiki mentions this)
- Is it legal to send multiple G1 commands on a single line, effectively using it as the separator (instead of newline)?
- Does Smoothie deal gracefully with multiple switches between G90 and G91? (as in, for rastering, I'd flip to G91, then back to G90 for normal vector work)

I've got Smoothie support running and I'm just trying to make sure the performance is as high as it can be.

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Saturday at 5pm a computer power supply shorted out, and it took a GFCI outlet and a circuit breaker with it. By 8pm I had a new breaker, a new power supply, and a new outlet, all installed, and I didn't have to call computer tech or an electrician. Being a geek has its advantages.
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My first ever piece of self-CNC'd furniture. I designed and built this from scratch, based on a table seen on http://becausewecan.org
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Joes 4x4 CNC Machine
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