Degree of Ellipse

[basty]

There are 45 deg, 60 deg, and so on, of an ellipse.

 

What is this degree mean?

 

Can somebody tell me how to construct a 60 deg ellipse in autocad?

[steven-g]

There is a saying "a picture is worth a thousand words". Does this help.

[Pablo Ferral]

Kudos Stephen.

 

Here's an article on ellipses in AutoCAD that you might find helpful.

 

http://cadsetterout.com/autocad-tutorials/converting-ellipses-to-arcs/

[steven-g]

I didn't know about the pellipse variable that will be useful, as I often need to use part of an ellipse for concrete formwork, and converting an ellipse to a polyline for the CNC can be fun to say the least.

[basty]

There is a saying "a picture is worth a thousand words". Does this help.

 

Yes, thank you.

 

Do you know what the degree of an isometric ellipse is?

[basty]

I wonder what is the use of these ellipse in different degrees for?

 

[fuccaro]

I didn't know about the pellipse variable that will be useful, as I often need to use part of an ellipse for concrete formwork, and converting an ellipse to a polyline for the CNC can be fun to say the least.

Steven-g

For more fun you may wish to read this old post: http://www.cadtutor.net/forum/showthread.php?1639-Anyway-to-Change-an-Ellipse-into-a-Polyline&p=14416&viewfull=1#post14416

[steven-g]

Yes, thank you.

 

Do you know what the degree of an isometric ellipse is?

I don't know, but I worked it out to 54.73561032°. An ellipse is just a circle viewed from an angle, so the various different ones you show are for that reason, for designers wishing to make visuals from varying points of view. I tend to draw them by using the UCS to give the correct values for the elliptical surfaces we need for precast concrete stairs.

 

 

Fuccaro

Nice work, but I have no option to use LISP in LT the pellipse variable looks really useful, normally I would use the multiple option from the pedit command to convert an ellipse segment, or use the offset command that also creates a spline, the pellipse looks to create what I need in one go, but I'll keep an eye open for any accuracy issues.

[basty]

I wonder what is the use of these ellipse in different degrees for?

 

[lrm]

An ellipse can be specified in a variety of ways including degree, major and minor axes, or conjugate axes (the red arrows below). For the 2D creation of isometric projections (or any axonometric projection) an easy way to create an ellipse in AutoCAD is to use the conjugate axes. In AutoCAD give the ellipse command followed by C for center (point 1 below), then click two points that define the conjugate axes (for example, points 2 and 3 below).

[rkent]

Irm - following your instructions that won't produce the ellipse shown, one of us is doing something wrong. Try your method and see if it actually gives the result shown.

 

An easier way is, while in snapstyl 1, start the ellipse command and use the isocircle option, pick the center of the ellipse and pick one more point.

[lrm]

rkent, you are correct in that what I posted will not work. I was working from faulty memory (mine). What I should have said was to first set the Snap type to Isometric Snap. Then, whether or not grid snap is active, you will get an option for Isocircle withthe ellipse command from which you set the ellipse center and a point on the conjugate axis of the ellipse.

This will give you one of the three isometric ellipses. I forget how to get the other two without rotating the one you do get by +/- 120°.

lrm