topic Re: Isometric geometry of objects around a center point. in AutoCAD Forum

Isometric geometry of objects around a center point.

Anonymous — Mon, 29 Aug 2016 01:06:28 GMT

I am trying to draw a disk with a diameter of 10" and a thickness of 3/8". It has 5 holes that are centered around the centerpoint of the disk at a diameter of 6". Each hole has a diameter of 2 1/2". I cannot figure this out for the life of me.

Thank You,

Karn

Re: Isometric geometry of objects around a center point.

Kent1Cooper — Mon, 29 Aug 2016 02:14:57 GMT

Are you drawing this in isometric, rather than modeling it in 3D? If so, get into isometric mode [Snap command, Style option, Isometric], and use the Ellipse command and its Isocircle option [which is not available unless you are in Isometric Snap Style] to draw Ellipses that are the isometric projections of Circles on one of the virtual-cube faces. [Read about isometric drawing in Help if you're not familiar with things like changing which face of the virtual cube you're drawing on.] Draw the outside 10" Ellipse [an Isocircle radius of 5], and another around the same center with a radius of 3 for the "path" that the holes are to lie along. Draw one hole as another isocircle, anywhere for the time being.

Then, to find the equivalent hole positions of equally spaced holes around the circle that the "path" Ellipse is a projection of, you can use DivideEllipse.lsp, available here, with its DE command. It will put Points at the correct locations around that Ellipse, and you can Copy the hole Ellipse from its center to those Points. Read the comments at the top of the file for how it places them -- if the result is not where you want them [e.g. it could start at a different quadrant than you want for 5 divisions], you can do it with, say, 10 instead of 5, and use every other location, or 15 and use every third, etc.

Re: Isometric geometry of objects around a center point.

Anonymous — Mon, 29 Aug 2016 02:38:23 GMT

I downloaded the item you linked but it just opens in NotePad. How do I make it work?

Thank You,

Karn

Re: Isometric geometry of objects around a center point.

Anonymous — Mon, 29 Aug 2016 02:49:20 GMT

Never mind Kent, I got it. Thank you for all the help.

Karn

Re: Isometric geometry of objects around a center point.

Michiel.Valcke — Tue, 30 Aug 2016 09:08:59 GMT

draw the top view in 2D and use the Extrude or Presspull command to turn it into a solid with the correct height. Set the view you want to have for the isometric view and use FLATSHOT to get a correct isometric view.

Re: Isometric geometry of objects around a center point.

Anonymous — Tue, 30 Aug 2016 12:16:12 GMT

Thanks.

Re: Isometric geometry of objects around a center point.

GrantsPirate — Tue, 30 Aug 2016 15:00:24 GMT

I would download a lisp file to do the iso view for you, TIP2052 at cadalyst.com. It is called ISOVIEWS.