Incircle Challenge

The Challenge is to use Xara accurately and create the Inclicle of the presented Challenge Triangle.

Attachment 126393

The Incircle is simply the largest one you can fit inside a given triangle.
The circumference therefore just touches the sides of the triangle and does not miss or go beyond the edges.

I am after solutions that are not best guesses or use calculations. The only calculation necessary is for checking the area of the circle is 111,800px², which Xara does automatically.

Your starter file is :pointAttachment 126395.
All Line widths given are 0px.

You should play to the strengths of Xara so I would expect lots of use of Snap to Objects.

Do describe your construction.

Hint: Clone and then Lock the original Triangle. Do then delete the Incircle; this is only there to demonstrate the accuracy of the expected solution.

Acorn

Ya lost me right off the bat, but thats not unusual for you acorn. But I will say I am going to take a look at it.

Here is my construction.

Attachment 126400

I felt like I was in the fifth grade in school.
But it was fun.

Servus

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Originally Posted by ernie-f

Here is my construction.

Attachment 126400

I felt like I was in the fifth grade in school.
But it was fun.

Servus

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ernie, thank you. This is the classical compass and ruler solution.

You are creating the angle bisector of the three vertices (only two are needed) to cross at the incircle position.
A circle centred here will then be easy to increase to touch the three sides when Snap to objects is active.

However, while your straight lines can be fixed to a vertex, I do not believe you can "accurately" position the other end point as there is no control or handle point available.

You can still manage and improve on this in a definite Xara-way.

@Xara - in passing, I tried with your Piesegment 1 Smart Shape. It is useless as when you try and position the centre with cursor keys the Snap to Objects FAILS and the JavaScript code is so slow, it FAILS to position. Might I suggest your Developers attempt this Challenge with Smart Shapes?

Attachment 126402

Acorn

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do not believe you can "accurately" position the other end point as there is no control or handle point available.

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You can do that with circles they snap in the midpoint too. Tis is the clasic way i learned over 55 years ago and don't forget.

Attachment 126403

Quote:

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Originally Posted by wizard509

Attachment 126403

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Sorry Larry, was it not clear that the circle doesn't yet exist? You have to make it.

The top left edge has an overlap with the circle and the bottom has a gap.
The Area is a little under at 111,300px².

Do correct me if I am wrong but I have no clear strategy for positioning the circle; I am adjusting, zooming in & out and working around the three sides.
I managed it in about 10 minutes.

Thanks for the approach though, it can be made to work.

acorn

Quote:

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Originally Posted by ernie-f

You can do that with circles they snap in the midpoint too. Tis is the clasic way i learned over 55 years ago and don't forget.

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ernie, I have no problem with Xara snapping circle centres, I simply cannot snap a line end (edit handle) to the crossing point of two circles and I cannot rotate a line exactly onto the same point. A line end will track along a circumference but when it crosses another, it does not snap.
I can position an edit handle very close to the intersection, go to maximum zoom and then use Alt+Cursor Key to creep into place. You cannot do this at a high zoom for a rotating line when the edit handle is a distance away.

Acorn

I've said this on MANY occasions. Xara would benefit from an ENDPOINT, MIDPOINT and INTERSECTION SNAP system the same as most CAD Systems. Although acknowledging that Xara ISN'T CAD, the technical side of the drawing system is similar enough to justify it.

Quote:

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Originally Posted by Acorn

Sorry Larry, was it not clear that the circle doesn't yet exist? You have to make it.

The top left edge has an overlap with the circle and the bottom has a gap.
The Area is a little under at 111,300px².

Do correct me if I am wrong but I have no clear strategy for positioning the circle; I am adjusting, zooming in & out and working around the three sides.
I managed it in about 10 minutes.

Thanks for the approach though, it can be made to work.

acorn

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I guess should have been more clear did make a circle zoomed 100% and sometimes 1000% to adjust the circle size I thought I had it but evidently not. Will look again. Sorry Acorn

Quote:

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Originally Posted by Acorn

ernie, I have no problem with Xara snapping circle centres, I simply cannot snap a line end (edit handle) to the crossing point of two circles and I cannot rotate a line exactly onto the same point. A line end will track along a circumference but when it crosses another, it does not snap.
I can position an edit handle very close to the intersection, go to maximum zoom and then use Alt+Cursor Key to creep into place. You cannot do this at a high zoom for a rotating line when the edit handle is a distance away.

Acorn

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Hi Acorn,
there is no problem with my construction. The lines I create snap all to the right points and are precise as Xara can be.
See the vid.

www.franta-net.de/ice/line snap.mp4

ernie, thank you, your video is very clear and I appreciate you taking the time to make it.

When I approach the intersection, I get the magnet pointer appearing when I am near or on the circumferences and the crossing but there is no real indication there the snap is the right one; it is this I am having trouble with, not your construction.
When I drag a line around, I have similar difficulty with the end points and the mid-point. At lower zooms, it all looks good, yet it is usually a lucky hit to get it exactly in place.

The only possible difference in our set-ups is I usually have scale line widths set. Thi make the line width important in snapping but here I have been using 0px anyhow, just like you.
I have checked Options > Mouse > Magnetic snap radii and I am using Point: 4px & Line: 3px.

In the end, I reckon I am saying that Snap to objects is most effective when the snap is to an Edit Handle. A crossing has no such handle.

Thank you for your patience.

Acorn

Yuo're right but you don't need a snap for crossing lines. This is only the referenz-point for the incircel and the three crossing line do snap for it in there cross.

Here is a detailed Hint about Angle Bisectors.

• Clone the Triangle and move it to a Guides Layer.
• Make two further Clones of the Triangle.
• Ctrl+Rotate both about a vertex until you snap an edge to the horizontal or vertical.
• Flip one Clone H or V, depending on the axis you have matched with. You should now have a Dart shape.
• Rotate the Clones back into place. I appended a short vertical leg to get this exactly right.
• With the two Clones selected, Add Shapes.
• Switch to the Shape Tool and delete all points apart from the point and the notch.

You now have the Angle Bisector.
The following diagram has an exaggerated Green Line for the solution and the two Clones were left in a vertical position before Adding to show the overall alignments.

Done properly all the construction shapes disappear leaving only the Angle Bisector, drawn to the full extent of the Triangle.
It all relies on Cloning and Ctrl+Rotation, without measurement.

Attachment 126408

Acorn

Here is my full design file:
:pointAttachment 126425.

Other approaches, comments and solutions are always appreciated.

Acorn