Unable to create contour geometry?

[scott_...@my-deja.com]

I'm trying to create a sweep with an elliptical cross-section. The
sweep path is a straight line. Guide curves are used to control the
shape of the cross section. I use 2 curves through the minor axis
points of the ellipse and 1 curve through a major axis point. I keep
getting an "Unable to create contour geometry. Please check the loft
section." error. I've tried a test part with a qualitatively similar
shape and it works fine. When I try it on the real part, I always get
the error. I've tried recreating the section, path, and all of the
guide curves to no avail. Does anyone know what is causing this?

Thanks in advance,
Scott

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[JC]

In article <7rrckk$nom$1...@nnrp1.deja.com>,

scott_...@my-deja.com wrote:
> I'm trying to create a sweep with an elliptical cross-section. The
> sweep path is a straight line. Guide curves are used to control the
> shape of the cross section. I use 2 curves through the minor axis
> points of the ellipse and 1 curve through a major axis point. I keep
> getting an "Unable to create contour geometry. Please check the loft
> section." error. I've tried a test part with a qualitatively similar
> shape and it works fine. When I try it on the real part, I always get
> the error. I've tried recreating the section, path, and all of the
> guide curves to no avail. Does anyone know what is causing this?
>
> Thanks in advance,
> Scott

If the sweep is a straight line...you shouldn't need any guid
curves....especially with two similar shapes (2 ellipses). Just select
each one at the same area and it will show the path....usuallt it picks
a vertix.
Are you twisting the loft between the two profiles?

As for the error.....try creating the loft without the guide
curves.....and see if the error appears.

In order to use the guide curves, the guide curve sketch must have
a "Pierce" relation to the ellipse sketches.

let me know if that helps,
JC

[scott_...@my-deja.com]

> If the sweep is a straight line...you shouldn't need any guid
> curves....especially with two similar shapes (2 ellipses). Just select
> each one at the same area and it will show the path....usuallt it
picks
> a vertix.

For clarity here: I'm using a sweep not a loft.

> Are you twisting the loft between the two profiles?

No. The guide curves "stretch" the ellipse. While the path is a
straight line, the guide curves are not. One is a sketched curve for
the major axis point. The other 2 (for the minor axis points) are
curves projected onto a curved surface. The ellipse maintains the same
orientation as far as the minor axis being horizontal and the major
axis being vertical. But, the shape of the ellipse changes as it is
swept along the path. I realize this is probably very difficult to
visualize. I could send you the test part (413KB) if you think it will
help.

> As for the error.....try creating the loft without the guide
> curves.....and see if the error appears.

From the above you can see why I need the guide curves.

> In order to use the guide curves, the guide curve sketch must have
> a "Pierce" relation to the ellipse sketches.

It is "pierced". But thanks for the reminder (I hate to get bit by
that one).

Thanks,
Scott

[David Murray]

scott_...@my-deja.com wrote:

> I'm trying to create a sweep with an elliptical cross-section. The
> sweep path is a straight line. Guide curves are used to control the
> shape of the cross section. I use 2 curves through the minor axis
> points of the ellipse and 1 curve through a major axis point. I keep
> getting an "Unable to create contour geometry. Please check the loft
> section." error. I've tried a test part with a qualitatively similar
> shape and it works fine. When I try it on the real part, I always get
> the error. I've tried recreating the section, path, and all of the
> guide curves to no avail. Does anyone know what is causing this?
>

Scott,
My immediate thought is the use of two guide curves controlling one axis of the ellipse. Is the ellipse centerpoint constrained in any way? If so, you should either unconstrain it or use only one guide curve per axis for controlling the elliptical profile.

Regards,
Dave Murray

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[scott_...@my-deja.com]

> My immediate thought is the use of two guide curves controlling one
axis of the ellipse. Is the ellipse centerpoint constrained in any way?
If so, you should either unconstrain it or use only one guide curve per
axis for controlling the elliptical profile.

One curve per axis works great! Thanks for the help.

-Scott