Rotating a line

I've been following a Xara tutorial recently where the instruction is to type a 6 degree rotation into the 'Angle of selection' box. This is to get a 6 degree rotation of a vertical line. When a vertical line is drawn, the figure in the 'Angle of selection' box is given as 90 degrees (because it's 90 degrees off the horizontal?). Typing in 6 degrees and pressing 'Enter', rotates the line to 6 degrees off the horizontal position and not the vertical as desired.

Is it possible to set the 'Angle of selection' box so that a vertical line is zero degrees as a starting point?

Hmm? This is a new feature added in the last update or two. And yes this seems a curious implementation of that feature.

That said, if the default setting for a vertical line seems to be -90 degrees. So, to rotate 6 degrees, change the angle of rotation to -96, eh? Or 96 to rotate anti-clockwise.

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Originally Posted by gwpriester

Hmm? This is a new feature added in the last update or two. And yes this seems a curious implementation of that feature.

That said, if the default setting for a vertical line seems to be -90 degrees. So, to rotate 6 degrees, change the angle of rotation to -96, eh? Or 96 to rotate anti-clockwise.

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Yes, that's what I did but not being too experienced, I got somewhat muddled at one point because I was following your tutorial for the Seth Thomas clock and trying to do all of the minutes accurately. I managed OK but having the vertical line at 0 degrees would have been good.

You enter #6 or #-6 to adjust six degrees of the current orientation.

Acorn

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You enter #6 or #-6 to adjust six degrees of the current orientation.

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Blimey (American expression). How did you come up with that? Is it documented anywhere?

Mart- The Seth Thomas clock tutorial was one of my favorites. I actually own that clock.

LINK

Stop trying to steal our language Gary ;)

@ Acorn, how do you remember all these obscure things?

@ Mart, it really pisses me off, a vertical line should have a rotation of 0 (or 180) not -90 !!!

Thanks everyone. I thought I'd tried all keyboard combinations to get a line to rotate a few degrees from the vertical position without having to add or subtract from 90. I'd searched widely before asking the question here too. I would never have thought to try the hash key plus the number. How it was discovered I don't know but many thanks for that Acorn. :) I'm sure it will help others searching for an answer too.

I have mostly used Xara for making greetings card inserts and doing a few simple graphic and photo effects but I've often looked with awe at some of the drawings you have all produced. I probably don't have enough years left to get that good :) but in these days of lockdown, I've had time to at least try something more involved. Thanks again to all.

I've finished the the clock face Gary. It turned out OK once I'd figured out how to draw the first 5 minutes (hence the vertical line question). Just started on the lower half. That ought to pass a few more hours/days of time. :)

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Originally Posted by Egg Bramhill

a vertical line should have a rotation of 0 (or 180) not -90 !!!

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that is certainly the norm in my experience, cardinal north [12-o-clock] for 0 deg

I guess xara must have had a reason back in the day for choosing horizontal plane, cardinal east [3-o-clock] for 0 deg - but it is another good reson for not using it for actual animaation [as opposed to asset] where is is the odd one out for me

I still have some programs that zoom 'the wrong way' with the mouse wheel.. that is irritating - back in the day things were not so 'standardised' ....

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Originally Posted by gwpriester

Blimey (American expression). How did you come up with that? Is it documented anywhere?

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In v16.3 release notes.

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Originally Posted by Egg Bramhill

@ Acorn, how do you remember all these obscure things?

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I just have a squirrel memory.

• https://www.talkgraphics.com/showthr...tation-Problem
• https://www.talkgraphics.com/showthr...otation-Angles

Acorn

I might understand why the # works. Pressing the hash key shows the grid, so if hash is something to do with the grid, then typing hash plus the degrees tells the program to rotate relative to the grid (whether it is showing or not). Well ..it's a theory. :)

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Originally Posted by Mart

I might understand why the # works. Pressing the hash key shows the grid, so if hash is something to do with the grid, then typing hash plus the degrees tells the program to rotate relative to the grid (whether it is showing or not). Well ..it's a theory. :)

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Sorry nothing at all like that, it was just a Xara whimsy. It didn't exist before v16.3.

Acorn

Nearly all CAD systems use horizontal (right) as 0 degrees and rotate anti (counter) clockwise from there, so 90 is straight up 180 is left and 270 is straight down.

A line to indicate one minute would be 84 degrees.

thanks keith I thought it might be that, but I don't use CAD; animation is different I guess

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@ Mart, it really pisses me off, a vertical line should have a rotation of 0 (or 180) not -90 !!!

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I would think the angle of rotation would be the original orientation of the line.

This does come in handy when I do some of my blended lines and shapes to create a spiral fill. Even though the start and end shapes start as vertical, the angle gets slightly changed for the start and end shape. So I can Ctrl select each shape and change the orientation. Not that it makes one bit of difference.

Shapes and Text come with a natural zero-degree alignment on creation such that if you hold down the Ctrl key you can ensure a snap to 0^o.
Enter a rotation angle greater than 0.113^o and Xara turns it into a graphic - @Xara - thanks for that - this needs sorting!

A box has a start node top-left.
A circle/ellipse, top-centre.
A QuickShape is top and furthest left.
Something created with the Shape tool has an obvious start node.

Xara then decided to follow the two-dimensional cartesian coordinate plane system (along the road and up the stairs - X-Y axes).
When the axes are drawn according to the mathematical custom, the numbering goes counter-clockwise starting from the upper right ("north-east") quadrant.
0^o is aligned to point from the Origin to the right , along the X-axis.
Xara then added a counter-clockwise arc beside its Angle of rotation box.

Instead of 0 - 360^o, Xara chose to represent angles as 0 - 180^o for the top two quadrants and -180 - 0^o for the bottom two.
This allows a vertical flip with the change of sign. 0 - 360^o still is acceptable input as are any angle over 360^o, they are just calculated as modulo 360.

A Line has to have its initial orientation included as without that all lines would degenerate to the horizontal when they were set to 0^o.

Acorn

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