export option and unexpected result

 From: -Gwozik- (PP) 31 Jan 2011  (1 of 6)
 Hello I've made a few export test to clearly undestand export options. Maybe my tests may help beginer to understand (or maybe I misunderstood how Moi work, so, do not hesitate to correct me.) ======= 1) Angle ======= First I created a circle and convert it to a surface (using planar tool) in order to test what happends when I change "angle" value (in the "meshing options" windows). For those who don't like mathematic : Complete circle = 360° When I choose 55° I get 7 polygons 360°/7=51,43° 55° is rounded to 51,43°. It seems logic When I choose 54° I get 8 polygons. 360°/8=45° 54° is rounded to 45° In this case, I expected 54° to be rounded to 51,3° (which is closer than 45°) I made a few other test : 76° is rounded to 72° (360°/5) 75° is rounded to 60° (360°/6) but is closer to 72° (360°/5) 26° is rounded to 24° (360°/15) 25° is rounded to 22,5° (360°/16) but is closer to 24° (360°/15) So, my conclusion is : mesh exported angle = ("angle" minus approximatively 5%) rounded to the inferior value. Where "angle" represent value in the "meshing options" windows. When trying to get precise polygon number this may help. But of course 99,99% users probably don't care (I know, I'm pernickety man) ======= 2) divide larger than ======= 2.1)-plane- I created 4 rectangular plane : 10x1cm 10x0.6cm 10x0.2cm 10x0,03cm Then I export using "Divide larger than" set to "1". As you can see : in the first three rectangle, rectangles are divided in polygon having width inferior to 1 in the fourth rectangle, rectangle are divided in polygons having width equal to 1 I didn't undestand why all the polygon have not the same width. But once more, I'm probably the only one intersted in such pernickety details. 2.2)-curved- I created a cylinder And I make test to understand "curved" first I only choose a value for angle then I add a value "Divide larger than"/"curve" then I add a value "Divide larger than"/"plane" (polygons don't seem regularly created) then I add a value "Divide larger than"/"all" When using 54°, polygons don't seem regularly created for both plan and curve : I don't know if this will interrest anyone, but my objective is reached, I now understand mesh export option.

 From: Michael Gibson 31 Jan 2011  (2 of 6)

 From: Michael Gibson 31 Jan 2011  (3 of 6)
 4012.3 In reply to 4012.1 Hi PP - also so for your #1 part regarding Angle - it looks like you're expecting a measurement from the center of a circle like this: But that's not actually how the angle is measured - the angle is actually measured as the angle between 2 adjacent edges of the polygon like this: The reason for this is that the mesher is meant to work on any kind of curved geometry, not only just circles, so it can't really focus on a measurement that only applies to a circular boundary alone (where there is some kind of separate center point taking part in the measurement). Additionally as I mentioned before the angle parameter is also applied between 2 surface normals as well, and that also works in this way as a measurement more between 2 directions and not as a measurement from some other center point as you were showing. Does that help to explain why the circle did not behave as you expected? The way the formula for the measurement works on a circle is: 360 / your_angle = number_of_segments_in_outline , with rounding going up. That measures your angle as the angle between the final segments, not the "sector angle" as I think you were looking at before. - Michael Attachments: