Help with solidworks needed

What exactly does this mean, Bob? Do you want the height of the extrude to vary cyclically with time (but the x-section.. ie your sketch, remains constant)?

Or do you want the path of extrusion (the centerline of extrusion) to follow some function between two bounds?

Thanks for the reply.

Neither, if I understand your question.

I want to sketch epicycloids and hypocycloids in the X-Y plane and then extrude the resulting sketches a fixed amount in the Z direction.

My problem is I do not know how to sketch arbitrary mathematical equations or functions in Solidworks. I could calculate a series of points on the curves and connect the points with a spline but the resulting sketch would not truly follow the mathematical equation and in my situation could create points of interference when the parts are meshed in an assembly.

Bob

The latest SW has 2D equation-driven curves. There are limitations, I think it can only do curves where y=F(x). It can not do curves where x&y = F(t), which is what I think you need for cycloids.

Pro/E would be perfectly suited for this.

I have generated true involutes using trace paths in COSMOS/Motion. Perhaps you could do something similar.

With any solution using SW sketches or curve-thru-points, pay close attention to the curvature of your resultant curve. If you trace a spline through a set of points, the ends may have errant curvature that will muck up the whole spline.

Can SW do curves in polar. I could convert the equations to polar (r=F(theta)) using the fact that r = sqrt (x*x + y*y) and theta = arctan(y/x).

Is this a problem if the spline is closed?

Bob

Not a problem with close splines.