How to create an elliptical lozenge type shape??

[Anonymous]

I’m trying to create a shape, but I’m not sure how to model it. I want to create what is probably best described as a lozenge. the profile is difined by the profile resulting from a section through any axis, x, y or z, which should be an ellipse. I can’t revolve half an ellipse as it will give me a circular profile when cut perpendicular to the revolved axis. I don’t think I can loft the shape as I need to get the smooth elliptical profile at either end…

So can anyone help me???

Thanks in advance,

Ian

[Anonymous]

I think it's called an ellipsoid. (Rhino has an ellipsoid tool for creating
the shape, anyway, so that's what I call it).

I think some have approximated the shape in MDT by scaling a revolved ellipse
(or a sphere?) asymmetrically. The resulting surfaces will be a bit
"troubled", but it may work for you.

You also may be able to get what you want by cutting one of the aforementioned
shapes with an arc (or other curve) and lofting off of the edges (1) to or
thru an elliptical section or (2) to a mirror of the first shape. IV has
problems with mathematically complex shapes, though, so sometimes it solves
and sometimes it doesn't.

========================

"iandouglas" wrote in message
news:f19183e.-1@WebX.maYIadrTaRb...
> I'm trying to create a shape, but I'm not sure how to model it. I want to
create what is probably best described as a lozenge. the profile is difined by
the profile resulting from a section through any axis, x, y or z, which should
be an ellipse. I can't revolve half an ellipse as it will give me a circular
profile when cut perpendicular to the revolved axis. I don't think I can loft
the shape as I need to get the smooth elliptical profile at either end.
> So can anyone help me???
>
> Thanks in advance,
>
> Ian
>
>

[Anonymous]

I think there is a scaling VBA program for IV. It will do X,Y,or Z.

Kathy Johnson

[Anonymous]

Ian:

One possibility is that you revolve the ellipse (or even a sphere), then
derive this into another part using unequally along the x, y and z axes.

Although this is not a native ability of IV, Sean Dotson and Brian Ekins
put together an add-in to perform this. Check out the thread 'Non
Uniform Scale Add-in Available' on October 2 in this newsgroup for a
discussion on this.

Richard


iandouglas wrote:
> I’m trying to create a shape, but I’m not sure how to model it. I want
> to create what is probably best described as a lozenge. the profile is
> difined by the profile resulting from a section through any axis, x, y
> or z, which should be an ellipse. I can’t revolve half an ellipse as it
> will give me a circular profile when cut perpendicular to the revolved
> axis. I don’t think I can loft the shape as I need to get the smooth
> elliptical profile at either end…
>
> So can anyone help me???
>
> Thanks in advance,
>
> Ian
>

[Anonymous]

I just tried it - beautiful.

Richard

[Anonymous]

Sean and Brian wrote it. Works great....

--
Cory McConnell
BJ pipeline Inspection

[Anonymous]

Wonderful. But editing the x,y,z scale once the part is derived isn't
possible or am I missing something. Shouldn't it be nice to get three
parameters added while deriving the part stretched?

Willy

[Anonymous]

Works a treat... Thanks very much.

Ian