Create a line Normal To an Ellipse

[embrypm]

I am attempting to build a tapered curve, using a basic ellipse as the base reference. In the past, using other tools I have done this by using a rather simple method.
1. I build the ellipse segment of interest
2. I create a set of equidistant points on that ellipse
3. I build a set of lines normal to the ellipse with the varying increasing heights
4. I create a curve through the endpoints of those lines and the resulting curve is tapered, following the ellipse with defined thicknesses at those specific points.

For some reason, Pro/e doesn't seem to want to compute the normal to the ellipse at the points i specify. I have also attempted to create a circle tangent to the ellipse at a defined point, thinking i could use that circle to find the normal, however pro/e will not allow me to make a circle tangent to the ellipse, at a particular point either.
I have attached an image showing an ellipse with a line coming from a specified point, when i attempt to add an additional constraint to the line, making it either normal or tangent, proe will not allow me to establish the constraint.

Thanks in advance!!

 

[kdem]

Make lines tangent to the ellipse at the specified points then make lines perpendicular to those. To get lines tangent to the ellipse at specified points, I'm assuming you are creating point entities in the sketch, you need to Divide the ellipse at those points.

 

[embrypm]

Breaking the curve did the trick in finding the tangent & normals....Thanks!!!

this does bring me to another question, if i wanted to place, say 10 points on the curve, equally spaced to break the curve at, how is this most easily accomplished in sketcher?

 

[dgs]

I'm thinking you'd be better off creating several features to do this.

1. Create your sketched ellipse.
2. Since the ellipse will be split in half, create a copy of the curve using the 'approximate' option to turn it into a single entity.
3. Create a datum point on the ellipse curve by ratio. Set the ratio value to 0.
4. Pattern the point using the ratio dim, making the increment 0.1. This should make you 10 points equally spaced around the ellipse. You can add a relation to tie the ratio to the number of points if you want: (ratio)=1/(no of points)

There are some new pattern tools available that may automate the spacing of the points on the curve without using the relation. I haven't played with them enough to know for sure.

You can then create a datum plane through the first point and normal to the ellipse, then pattern it to get the series of planes. you can then make your sketch of perpendicular lines. Because of the varying length of the line segments, you probably can't pattern them unless you create the point and plane on the fly when creating the sketch.

It's a lot of steps, but not really a lot of work. I'm not sure why Pro|E won't let you make a line normal to an ellipse.

 

[embrypm]

Thanks everyone for the help....very much appreciated!!