Hi Jacobs,

I think there are two issues in your file. First, I see that you are drawing the Parent object local axis, which is good! I guess you noticed the local axis is located at the center of the curved surface. Now, you’ve left the Center X, Y, and Z values at 0.0. This is the first problem because, after that you’ve defined the axis vector (columns: Axis X, Y, and Z) as pointing along Z only. The Help File for the axis vector reads:

The axis of rotation must not intersect the object, or an invalid solid will be generated

Your current situation is as depicted:

The axis of rotation vector (or simply called axis in the columns of the Swept object) goes through the center, which is located on the origin of the Parent local axis, which is forbidden.

The second problem is that you seem to be trying to slice the standard surface with the slicing plane. This creates a curve that doesn’t have a surface. Hence, it isn’t a cross-section anymore. If you don’t apply a radius to the standard surface (its a circle) and have the slicing plane co-planar with the circle, then it works. It creates a thorus:

Can you tell us what sort of surface you’re trying to achieve? There might be a better way to do it than with the Swept object.

Hope this helps, take care,

David

Thanks David!!!  OK, I’m straightened out now on your first point--I did not correctly understand the coordinate systems.  But I’m still confused about your second point: that when I “slice the standard surface with the slicing plane, this creates a curve that doesn’t have a surface.”  I think maybe you’re saying that the parent object needs to be an object whose intersection with the slicing plane is a closed curve?  That seems correct, because I can make Swept work as expected with parent objects that fully enclose a volume, like Standard Lens or a CPC with the Volume flag turned on--but not with surface objects like Standard Surface, Cone, or the same CPC with the Volume flag off.  But then how do I interpret this part of the Help file:

The parent object may be any surface or solid volume. A cross section of the parent object is formed by the intersection of the parent and a "slicing" plane.

You ask what am I trying to achieve?  I’m just trying to use some simple examples to learn how to use Swept before applying it to some more complicated problems.

Thanks again!

Ben

Hi Ben,

That’s what I was poorly trying to say! While I agree the Help File could be clarified, I think the key is in the second sentence:

A cross section of the parent object is formed by the intersection of the parent and a "slicing" plane

It seems that if this formed cross section isn’t a closed surface it doesn’t work.

Take care,

David

Hi David, Ben

On the same subject.

I was trying to create an elliptical volume using the swept object with an ellipse surface as the parent object. But to do so, the rotation axis should be on the parent object (360° sweep angle around the large axis of  the ellipse for example). Do I understand correctly that this is actually not possible. Do you see another way to create this elliptical volume?

Thank you

Renaud

Hi Renaud,

Is an ellipsoid what you are after? If that’s the case, it probably wouldn’t be possible with the Swept Object as you’ve already figured out.

I don’t have a licence at the moment to confirm so don’t take my words for granted, but it might be tricky to make such an object (except for a perfect Sphere for which there’s a Sphere Object) with native objects. You might have to resort to making your own user-defined object. I may be able to help with that as soon as I get a licence :p

Take care,

David

Hi David. 

Thank you.

Hi Renaud,

Please have a look at these two posts (sorry for brevity I have to rush now):

Hopefully you’ll find something useful :)

Take care,

David