Elipse in 3D sketch

[tommy104]

Anyone know how to get an elipse into a 3D Sketch?
I have set up my work planes to make a closed loft
in order to make a ring shaped object. I want the
loft sections to be eliptical. Why are the elipses
ghosted out in 3D sketch? Is there a work around?


Thanks,

Tom

 

[TheTick]

No ellipse in 3D sketch. If you really need an ellipse in a 3D, you probably need to make a series of 2D & 3D sketches. Possibilities:
[ul][li]First draw ellipse in 2D sketch, then use "convert entities" in 3D sketch to get ellipse.[/li]
[li]If ellipse is used as a fillet, draw entities that ellipse fillet joins in 3D, make datum plane from those entities, then make ellipse in 2D sketch[/li][/ul]

Once you have all of the segments drawn, you can unite them with composite curve or another 3D sketch

 

[tommy104]

I found that if you make a spline into a loop and
connect it to itself it makes a decent looking ellipse.
I Snapped it to four dimensioned construction lines
to make it controllable and symmetrical on two axes.


-Tom

 

[GBor]

I haven't tried it, but could you draw a cylinder, cut it at an angle and convert entities on the cut surface?

Garland

Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group

 

[GBor]

Just tried it...guess it might be difficult to get the right sized cylinder, but if you've already created an ellipse that is "close enough", but you want it to be cleaner, extrude the ellipse, cut it off flat (one of the major planes), convert entities on the circle that results from the flat cut and use it for the extrusion to get a "pretty" ellipse.

 

[handleman]

The right-sized cylinder shouldn't be too hard to figure out, I would think. Cylinder diameter is the minor axis size. Angle of cylinder to the plane of interest can be found using arcsin or arccos of minor axis length divided by major axis length.

 

[GBor]

Been too many years since geometry...thanks, Handleman! I homeschool my daughter in math and geometry is the coming year...guess I'll remember it then

Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group