
Re: Ellipse Circumference Sketch Dimensions
Dwight Livingston Aug 29, 2009 11:40 AM (in response to Peter Hunstein)You could get an approximate value by plugging in the formula
"y_axis"= 2*(((("ellipse_perimeter"/pi)^2)/2  ("x_axis"/2)^2)^.5)
where you assign x_axis and ellipse_perimeter to drive y_axis.

Re: Ellipse Circumference Sketch Dimensions
Kelvin Lamport Aug 29, 2009 12:41 PM (in response to Peter Hunstein)Is the end shape a true ellipse, or just a squashed circle?
Re: Ellipse Circumference Sketch Dimensions
Peter Hunstein Aug 29, 2009 2:00 PM (in response to Kelvin Lamport)The die that is used to form the tube was machined from an extruded ellipse. What comes out is probably as close to squashed circle as it is ellipse but on the model using this tubing it is supposed to be an ellipse. Making the Y dimnesion a function of X and the circumference constant would work but if I could just lock a dimension of the circumference that that would make things a lot easier.
Re: Ellipse Circumference Sketch Dimensions
Dwight Livingston Aug 29, 2009 8:35 PM (in response to Peter Hunstein)I don't know what you mean exactly by "just lock a dimension of the circumference", but here's a part that shows how you might use equations with dimension you can adjust. I made it so you plug in the original pipe diameter. You can vary the driving diameter and the x axis dimension.
Hopefully this will inspire someone who knows what they're doing to show how it's really done.

elliptical pipe.SLDPRT.zip 68.4 KB

Re: Ellipse Circumference Sketch Dimensions
Harold Brunt Aug 31, 2009 8:21 AM (in response to Dwight Livingston)Not to say that the "someone who knows what they're doing" is me but you set it up as I would. (I read this post on the weekend and pulled it up first thing this morning to see what you did  yes, I'm a nerd). Wouldn't it be nice if the formula would update without a rebuild or is there a way to make that happen?


