What is up with triangles in Illustrator?

[OppelWoW]

What is up the basic triangle in Illustrator?  This has bothered me for years.

Its default center point is always off compared to other shapes.  It is never actually center.  Which throws then throws off the rotation.

It also doesn’t act the same as other shapes with the free transform tool.

If you use a tringle as the shape for in this tutorial the results are quite different compared to other shapes.

[Monika Gause]

Please post bugs & feature requests to http://illustrator.uservoice.com

[OppelWoW]

Thanks.  I had tried looking for something what you suggested.

[Doug A Roberts]

The centre point of a triangle in Illustrator is the centre point of its bounding box. This is true for all shapes -- not noticeable in things like ellipses and rectangles, where the centre of the bounding box and the centre of the shape coincide.

[OppelWoW]

Thanks.  Couldn't think of the term bounding box when I made my post.

It makes sense the way it works, but I have never liked it.

This still doesn't answer why triangle acts the way it does in try it as the shape in the tutorial.  

[Doug A Roberts]

The tutorial link you posted doesn't work so I can't see what you mean.

[OppelWoW]

Yes.  I messed up really reallu bad.  Not only did I rush the whole thing, but I didn't proof anything.

For that I humbly apologize.  There was no realy excuse.

Here is the link - https://www.youtube.com/watch?v=ceufglnNPKI&t=203s

[Doug A Roberts · Accepted solution]

As per @Kurt Gold 's pointer later in this thread, you need to keep the triangles as live shapes to have them transform around their geometric centre rather than the bounding box centre. In one of the first steps there, the presenter uses a zig zag effect, then expands it -- making it no longer a live shape.

If you create the second triangle before you expand them both (scaling with 'Scale strokes & Effects' checked in the Transform panel), your smaller triangle will scale to its geometric centre.

[OppelWoW]

Thanks.

[Ton Frederiks]

As Doug mentioned, the rotation center is the center of the bounding box.

This script "Circumcircle.jsx" shows the real center by drawing a circle around the object.

https://github.com/Shanfan/Illustrator-Scripts-Archive/blob/master/jsx/Circumcircle.jsx

[OppelWoW]

I have done something similar to get the center of a tringle.

That does not help with help with doing the tutorial.

[OppelWoW]

I forgot to thank you for you answer.  So you you for responding.

Also I messed up the link.  I apologize.

Here it is - https://www.youtube.com/watch?v=ceufglnNPKI&t=203s

[Jacob Bugge]

Oppel,

In addition to what Doug and Ton said, to get just a clearly visible centre (even when unselected) to click for your rotation, you can select the triangle and Alt/Option+Ctrl/Cmd+J or Object>Path>Average with the default Both, with Round Cap in the Stroke palette; without the Round Cap you will need to rely on your friends Smart Guides to find it, but you know where it is so you can also use it as visual practice.

As with the exquisite circumcircle (by 佐藤浩之, Satō Hiroyuki), you get an additional path which can be deleted when you are sure that you have finished rotating.

[Steve Fairbairn]

Hi Jacob. There's also the old trick of adding anchor points and drawing lines from the corners to the opposite anchor point. Where the lines intersect is the geometrical centre. You can convert those lines to guides and group the to the triangle so that you can always find that centre again.

[Jacob Bugge]

Hi Steve, so great to see you.

[tromboniator]

Steve! I'm delighted to see you again.

Peter

[OppelWoW]

I will try out what you suggested.

In the past I have dome something similar to the image in Dougs post.

This still doesn't answer why triangle acts the way it does in try it as the shape in the tutorial.  There is no real easy way to do that.

[Steve Fairbairn]

It's not just triangles that behave this way. Any regular polygon with an odd number of sides behaves the same way, as do all irregular shapes. But Auntie Illie, being basically stupid, doesn't know this and puts everything in rectangular boxes. 😉

[OppelWoW]

Thank you.  That does make sense.

[Jacob Bugge]

Oppel,

There is no way that the centre of the Bounding Box can coincide with the centroid/geometric centre of a polygon with an odd numer of sides.

https://en.wikipedia.org/wiki/Centroid

There is no link to the tutuorial, but I believe that it may have incorporated a nofill/nostroke circumcircle forming a Group with the triangle, in which case you can just rotate freely in any way you wish.

And what Steve said, apart from the word stupid: she likes to challenge us and keep us on our toes.

[Steve Fairbairn]

Perzackly. Silly old Illie.!

[OppelWoW]

Hi,

I messed up rather royally on that post.  I rushed it and didn't proof anything.  I apologize for both that and if I came off as a jerk.

Here is the link - https://www.youtube.com/watch?v=ceufglnNPKI&t=203s

Thank you for the info on the centroid.  That does make sense.

I do not understand the Steve thing.

[Steve Fairbairn]

What "Steve thing" is it you don't understand?

[OppelWoW]

I didn't understand this part.  "And what Steve said, apart from the word stupid: she likes to challenge us and keep us on our toes."

[Jacob Bugge]

Oppel,

Steve and I are referring to Auntie Illie, also known as (just) Illy; the two spellings seem to have met when the Mac and Win tribes merged a good decade ago (many names are found in corresponding forms, ending in ie/y. Her job description is Adobe Illustrator, and she is always eager to help; some think that she sometimes moves in mysterious ways (some think she always does).