@terribleperson: I forgot to address your question about the ability to print longer arms. I have stretched and skewed the geometry of Simpson in many different ways to see if the ability to print longer arms is inherent or I just got lucky. The answer is that for any reasonable geometry that you would pick leads to being able to print longer arms. I am going to coin the word "macrocreation" to describe the process of creating a larger version of oneself. To design a Simpson there is really just one ratio that matters. That is the arm length vs distance between the shoulder pivots. I am currently using the ratio 3:5. Mathematically, you get the biggest volume as the ratio goes to infinity meaning the shoulders get closer together. However, your print volume becomes flower shaped as the area from the shoulder pivots radiating out become a no man's land. The flower shaped volumes have the potential to print much much larger arms. It just wouldn't be good for everyday use. I moved the shoulders apart until I got the bulk of the theoretical print volume to be between the shoulders. Currently, Simpson has the shoulders spaced at 250mm and the arms are 150mm. Simpson can technically reach all positions on the print bed plus quite a bit off the board. I purposely truncated the print area because the available height goes down to zero at the edges. Bottomline, any Simpson reasonably designed will happily be able to participate in macrocreation. A 3:5 Simpson can have a macrocreation factor of .67. (67% longer arms) A 3:4 Simpson has what I consider the practical max for the macrocreation factor of 1.1. (110% longer arms)
Here you can see an animation where it goes from a 3:5 Simpson to a 3:4 Simpson. I scale the width of the possible arm print to be proportional to the length.
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Here you can see an animation where it goes from a 3:5 Simpson to a 3:4 Simpson. I scale the width of the possible arm print to be proportional to the length.
