Quote Originally Posted by mike_biddell View Post
I do have some concerns about absolute printed dimensions in relation to the designed dimensions i.e. will the peachy output dimensions exactly match the design input dimensions. Since the base level Peachy is analogue, calibration becomes critical. It's no good printing a set of gears, if the dimensions are out, they wont mesh !!!! There are a lot of variables and the software will have to be quite clever to calibrate against mirror angle. A small change in the mirror angle when the beam is at a large deflection represents a much larger dimension than when the beam is vertical to the surface. So deflections will have to be progressively mathematically weighted (a reduction) as the deflection increases. I presume it is this factor which has dictated that all the example prints so far have had small deflections (small x and y). It's quite a complicated bit of maths to do the off axis deflection compensation to maintain absolute dimensions.
X and Y are proportional to tan theta multiplied by the height above the resin, where theta is the angle with the vertical. This is reasonably sensible for +/- 45 degrees, but above that deflection, tan theta goes a bit wacky......... +/- infinity at 90 degrees. So you would probably want to limit mirror movement to +/- 45 degrees for the function to remain sensible.