Verify a quadrilateral

Hi everyone,
I want to verify if a quadrilateral is a rectangle or not.
I thought may be about the angles ( if one of them is different from 0.5*Pi )
Thank you

Probably a million ways to do this; here is but one. BTW, I didn’t use Equal to test for equality of areas because of floating point errors, a common complaint on this forum.

is (9.9 KB)

1 Like

I think the first thing you need to check is if it’s planar or not.

thank you it works correctly

It will not work in some special cases…

is (11.9 KB)

" Nothing will ever be attempted if all possible objections must first be overcome." - Samuel Johnson

I assumed that @Maya_Lily knew what kind of shapes she was working with, but here’s something to address the degenerate quad case.

is (12.0 KB)

In general case, an arbitrary curve is rectangle if:

  • is closed curve
  • is planar curve
  • is polyline
  • all angles at discontinuity equal to Pi/2 (20.2 KB)

my question was just for quadrilaterals, but I have more shapes (rectangle, rectangle+arc, rectangle+2 arcs, segment++arc, cercle, ellipse and “other”)
Like in the file below

base_identification (16.6 KB)

some basic type of curves… (7.6 KB)

it’s ok for circle and elipse. But for unknown i want to identify them more in my case i Have : “rectangle”, “segment+arc”; “rectangle+arc”; “rectangle+2 arcs” and “other”
So in total I have 7 types

Why didn’t you asked for this in the beginning? People could save time if you can’t even need their solutions to your initial question.

I said that the solution of @akilli is ok for me and I thank him a lot for that :slight_smile: , so I added his solution to my original work… but when people continue trying, I mentioned that my purpose is not to evaluate all the shapes in the world just the seven types related my work… I didn’t want to ask about everything to don’t think that I need someone to work in my place, it was just a question about somenthing specific that I can reshape according to my need… :slight_smile:
So I’m not loosing people their time, if it’s true I’m sorry @tim.stark

Forget it. My bad sorry! Didn’t read everything right.

1 Like