Tangent through a fixed point on an ellipse

This issue must have been covered in this forum in the past, but I could not find any relevant topics when I did a quick search. So here goes...

I have an ellipse with a series of datum points placed on its perimeter. How do I draw a tangent & normal to the ellipse located at these points?

I have been struggling with this in the sketched mode, but for some reason wildfire will not allow me to force a tangent line to pass through a predefined point.

I might be able to eventually figure it out by writing up mathematical equations, but thought there should be a less painfull way of doing this.

Thanks

Tim

Reply to
tim
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You can do it, but ellipses, conic arcs and splines tend to confuse the sketcher constraint solver every now and then. (I've had problems getting the constraint, shut down and re-started Pro/E, and then could get everything to work. Go figure...)

I've also found working with "centerlines" (vs. "lines") to be more problematic (wants to break the conincident constraint before allowing tangency).

If all else fails create planes normal to curve thru pts and reference them.

If you want to see how it's "supposed" to work; sketch an ellipse, drop a sketch point on it, start a line on the sketch point and "rubber band" the line around, approx tangent to the ellipse, and you should see a "T" highlight when within constraint tolerance. Shift + RMB when it's visible to lock it in and finish creating the line segment.

Reply to
Jeff Howard

Are you using the Intent Manager?

Reply to
shaun

Tim, as long as the datum points were created on the curve..length ratio/actual len you should be okay

create a datum axis tan curve.. pick ellipse, spline .. curve then the point create another datum axist >point normal plane the plane the curve is on and then point you will use it later

now create a plane thru you tan curve axis , normal to the plane the curve is on and finally another plane thru the point norma plane axis and normal to the plane you just created

now you can move all around the curve/ellipse by modifying the length ratio point, it doesn't do it in sketcher ..but if you need is to put a cut /hole/ extrusion at at tangent point later into the curve/spline/ellipse it works

Reply to
cad/cam/guy

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