Cheers… I did just that… And with a circle, I have had ZERO problems… But doing the same with a Hex has caused me a whole world of problems.
So I am sorted now… But I just wanted to check if there was a different/better way than the way I do it (for example the OffSet tool)?
But as long as I am doing it the right way, I am happy…
Cheers
Jon.
actually… I am STILL not entirly getting it… I tried something again…
I set Precision to 0.00000 and I have a random hole which is 5.004146mm wide… So to test the accuracy, I wanted to get it to 5mm…
So the difference is 0.004146, so the radius is 0.002073
I therefore figure that if I move the edge of the hex by 0.002073 the result should be exactly 5.000000mm.
But its not… Its 5.003971mm… And if I do it again, I get different results each time.
Am I being stupid here and missing something really obvious?? I am really sorry to keep on, but this its really annoying me that I don’t get this.
Jon
I tried to reproduce the error you were seeing, but it kept on working fine for me. Even if I don’t draw the polygon lined up with the axes, the resizing by moving the cardinal point method still works.
Are you getting confused about which radius you’re talking about? I noticed that you were moving a cardinal point on an edge. Regardless of which method you use to draw it, Entity Info reports the radius of an inscribed circle i.e. the length of the shortest line from the centre to a vertex. If you move the edge by 0.1 towards or away from the centre you will not be changing the radius as reported by Entity Info by 0.1mm.
To switch between the two drawing methods press and release ⌥ on a Mac or Control key on Windows. While drawing the polygon, next to the Value Control Box it will either say “Circumscribed Radius” or “Inscribed Radius” and you’ll see the outline of a circle while you draw to show the method being used.
For example if you draw a circumscribed hexagon and type the radius as 10mm and immediately look at Entity Info, you’ll see 11.547005mm which is the radius of the inscribed circle.
I don’t have a problem with 2D Hexs… Its when I make this I have a problem…
test.zip (464.8 KB)
So this is just a curiosity thing now… You will see that the hex hole has a diameter of 5.00853mm.
And I am trying (again out of curiousity) to make it 5mm… I know it would be easier to delete the hole and draw it again at exactly 5mm, but I am just trying to understand something.
So I select the move tool and click here:
Then i drag towards the middle and finally type 0.0004265 (which is 1/2 the diameter)… According to my maths, that should make the hole exactly 5mm…
But it doesn’t
And even more curious, if I do it again I get a different number each time:
And sometimes the hole gets bigger…
I am never going to work to this level of precision… But I am now obsessed with finding out what I am doing wrong…
Are you using a midpoint of an edge of the hexagon or one of its vertices to resize it?
Actually I can see it not working very well or at all here if I use the midpoint. I have to go off for a while, but I’ll have another look later. I can understand that circumscribed would be the right way to draw it for you so it fits the ball bearing. You might be quicker drawing a row of hexagons each one a small increment bigger than the previous one. Print them all at once and see which one fits best.
If you use the midpoint, it’s just not accurate at all. If it snaps to another line, it’s not exact and there’s an error. If you do the same with a vertex it snaps exactly to guidelines or other inference points.
Using the midpoint cardinal point to resize the hexagon also showed some buggy behaviour if you moved the mouse perpendicular to the direction of size increase. In the GIF, I snap to a guide that should make it 2.5m but there’s an error. Then I snap it to a line and the size varies as I move my mouse along the line. I then locked it to red and the size shouldn’t be changing at all, but it is.
I wonder if you are (a) working at normal size (ie, your screenshots are reporting the hole as about 5mm radius) because if so (b) you should be working scaled up 1000x and work in metres as if they were mm.
If (a) is true you are probably running into SU’s small edges problem. Originally, SU was designed for architects, and to keep things intersecting correctly, assumes that any points closer to each other than about one thousandth of an inch were intended to be the same point - for an architect, that is still several orders of magnitude smalleer than the real world sizes of things they were modelling. So it still does that.
If you are drawing small items, or trying to make very small moves (as you are) you will get the kind of confused results you report.
If you look at the post just before this one, by @McGordon, you’ll see he’s done that - scaled up to metres.
Try doing that, and see if you get predictable and consistent results.
You can use the "Dave method ", attributable to Dave Richards - search the forum for that term.
It involves scaling up a copy of your normal sized model, Zoom Extents to see it, editing the enlarged copy, then deleting it - then Zoom Extents again, back to view the small original.
The edits are shrunk down to the original scale. SU can’t create very short edges, or make very small moves but can shrink them and keep them on the small copy if you make them on the large one.
At least some of the smaller moves you are trying to make are less than one thousandth of a** millimetre** and many are still less than one thousandth of an inch, and less than one hundredth of a millimetre.
