Radial lines in a group created with Polar Grid Tool don’t touch the outer ellipse precisely
After creating a shape with the polar grid tool, if you want to create the shape of any region on the outermost layer, you cannot. Because the anchor point connects to the outermost layer and does not cut it. In the examples I will give below, I am trying to shape the area I indicated in blue with the (Shape Builder) tool. However, we cannot cut the shape because the section line does not touch the upper part. It must be a mistake to connect to the inner part of the circle correctly, but not to the outer part. You can also try it yourself.
Volkan Sabuncu
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I confirm that.
I remember noticing it when using Pathfinder, to have separate sectors, but I never studied the problem.
Thank you for reporting this.So far I am seeing two somewhat simple workarounds:
1. Enable Gap Detection option in the Shape builder Tool Options — it’s usually is disabled by default
2. or tweak the tolerance in the Pathfinder Options, from the panel’s menu
...or scale the shape 10% — the gaps will become small enough for the Shape Builder to ignore them — and then scale back to 1000%.The reason why it happens is both simple and complex.
A circular ellipse with 4 points in any vector editor in not a REAL circle, but a close enough approximation of it. This is how Bezier curves work. Radii lines meantime have the exact lengths. You can check it with a normal ellipse, or by creating a polar grid with 4 sectors and checking the gaps in it.Technically Ai could have calculated a better approximation of a circle in these case, by adding more points for these... as an option, of course, to not break possible workflows users can have with this quite basic tool (not everyone would respect 5-pointed circles).
Take a look at these two related UV entries:
1. http://illustrator.uservoice.com/forums/601447/suggestions/34684633 — this is very the Ai team had to cheat to make live shapes to tell a lie about a diameter being a constant value, to hide the reasoning (after all, it’s complex enough to grasp). If once converts a live Ellipse into a path and rotates it — Ai will tell the truth, and the 'diameter' (width or height really) will cahnge.
2. https://illustrator.uservoice.com/forums/333657/suggestions/33499646 — 'Circles in Illustrator are not accurate' ...well, they never are in Bezier’s math.
