Stretching/forming question

[RFAB]

I'm trying to perform what I thought was a simple sketch proceedure and I'm running into a road block. I'm trying to take a 5" circle(sketch) and distort/stretch it into a teardrop shape but I need to maintan the circumference(using SW 2010). Is this even possible or am I just making it up in my head? I know I could just sketch arcs and radii until I get what I need I just thought there was a more simple way to accomplish this task and I cannot seem to get it done

In the end I intend to print off the final sketch as a 1:1 drawing so I can lay it over a block of wood and carve out the shape to make a simple die set that will allow me to take a thin wall(20gauge) 5" steel tube and compress it into that rough teardrop shape in a hydraulic press.

thanks folks!

 

[Updraft]

It sounds like your constraint is the 5" tube you have available. I am not a fan of stretching as you have described and would recommend that you make your sketch by drawing a circle and adding the two tangent lines to make the teardrop. Trim the circle or draw it initially as an arc. Now if you want the teardrop to have the same perimeter as a 5" circle you simply need to add appropriate dimensions. I would suggest using an arc length dimension and then the length of the straight lines. You should be able to make this match the 15.708" circumference of a 5" diameter circle.

- - -Updraft

 

[RFAB]

Yeah you're right on the money there. I went ahead and just sketched some arcs and kept mvoing things around a bit until I got it to fit withing the parameters I needed. Juggling around a little math and a few test sketches I was able to get it to 15.62" without much difficulty and given what it's meant for it's well within any sort of tolerance for the job.

I thought there was a way to set some constraints to lock the circumference and then set a few points that you could drag around where SW would retain the set constraints(Ie circumference in this case) as you moved the points to the new desired shape.

Thanks for the assistance sir!

 

[Jboggs]

First, SW sees circles (or arcs), and ellipses as two different geometrical entities.
You can set arclength as a constant. I've done it.