I want to start running a CNC mill based on my sketchup drawings. I am going to make aluminum parts for my truck and then market them once I have them correct.
Sketchup is all I have ever used but never in a way where my drawing will directly transfer to a machine for cutting. My main worry is how many segments to draw to have a nice final CNC product.
When looking for a circle segment rule of thumb I came across this post and have applied some of the math into a spreadsheet to understand what my limitations might be.
From your post I have come up with this to complete calculations in excel
degree 1 (d1) = 360 degrees / Segment # (S#)
degree 2 (d2) = d1 / 2
Radius of circle (r) = Perpendicular length from segment midpoint to circle center (PL) + Versine (TOL)
PL=r-TOL
Cos(d2)=PL/r
Cos(d1/2) =((r-TOL)/r)
Cos(360/(2*S#))=(1-(TOL/r))
Cos(180/S#)=(1-(TOL/r))
(180/S#)=ACos(1-(TOL/r))
S#=180/ACos(1-(TOL/r))
r=TOL/(1-(Cos(180/S#)))
For excel:
S#=(180/(DEGREES(ACOS((1-(TOL/r))))))
r=(TOL/(1-(COS(RADIANS((180/S#))))))
For drawing small parts accurately I typically scale up 1 million to 100 million times to make the number entry without decimals. This totally eliminates the failures of sketchup with small dimensions.
What I find is sketchup starts to get slow or crashes when I use large numbers of segments. What I have found is past 100 segments some extensions do not want to work correctly.
Based on a limit of 100 segments and a Versine tolerance of 0.001 inches that will limit me to a radius of 2 inches. Sketchup will allow 999 segments but I doubt the program will function.
Now to my question:
Is there an intermediate program that I can import my low segmented circle sketchup model into to ready the model for printing or cutting smooth circles. This would allow me to continue to use sketchup instead of learning another CAD program to facilitate my CNC work.