topic Parallel ellipses in Modeling

Parallel ellipses

Anonymous — Sun, 01 May 2005 02:46:21 GMT

Hello,
I am trying to find a way of drawing two exactly parallel ellipses,
one a certain amount larger than the other.
Copy and past a copy then stretch does not work.
Offset with the marque tool does not work.
The first method just scales the major and minor axis which
does not make a parallel ellipse.
The second method makes an aproximation using arc segments
not an elliptical arc.
Drawing two lines the same length, one from the major axis end point,
and one from the minor axis end point and then drawing another ellipse
using the line end points as the major and minor axise,
does not work.
As I remember from paper and pencil days, one could do this
with ellipse templates of matching percent.

Any thoughts, comments, suggestions ?
Thank you,
Peter Devlin

Re: Parallel ellipses

Dwight — Sun, 01 May 2005 06:24:51 GMT

You have posed a great question...... have you considered magicwanding a wall around the outside of your first ellipse and using it as a guide for the new ellipse?

Re: Parallel ellipses

Anonymous — Sun, 01 May 2005 06:51:46 GMT

Try resize

Re: Parallel ellipses

Dwight — Sun, 01 May 2005 06:56:43 GMT

Julia - that's a very realistic object you made. I understand they are also parametric but once they start to stretch, they won't go back.

Perhaps you can help me with a GDL script:

In my script, the protagonist [Tom Cruise] faces the ethical dilemma of applying the published GDL standards while making objects or shortcutting the quality of the object to make the big bucks. As he ponders this question, do you think it would be a good time for a car chase?

Re: Parallel ellipses

Anonymous — Sun, 01 May 2005 07:23:11 GMT

Yes very realistic, very time consuming and as much as I would like the big bucks it's not going to happen for at least 6 years.

As for the car race - I'm more excited about motor bike races.....

Re: Parallel ellipses

Anonymous — Sun, 01 May 2005 18:07:20 GMT

Dwight,
I had not thought of that method.
I tried it and it works. Interestingly, the walls are composed
of arc segments that very closely follow the inner ellipse.

I am beginning to suspect that concentric parallel ellipses are
mathematically impossible. I did a search in some math sites
and I found a drawing of concentric ellipses,( the drawing was
titled parallel ellipses), but they were not parallel in the sense I mean,
but just concentric and of the same "percent" (ellipse templates)
and equally spaced as measured from the major or minor axis.
I wonder if some mathematical type might comment.

Thank you,
Peter Devlin

P.S.
Julia, resize does not do it. It just scales the major and minor axis.

Dwight, In your post you refer to a library part that Julia made.
I don't see any library part attachment posted by Julia.

Re: Parallel ellipses

Dwight — Sun, 01 May 2005 18:08:46 GMT

The runt. One way stretch = growth.

Also --don't forget that magic wand controls tolerance for matching wall and ellipse.