# Help with solidworks needed

• posted

I am a student who is just beginning with solidworks. I want to create a sketch that I can later extrude that follows mathematical equations. In particular at this time epicycloids and hypocycloids. I would appreciate any advse on how to easily accomplish this task.

Thanks

Bob

• posted

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?

• posted

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

• posted

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.

• posted

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

• posted

Not a problem with close splines.

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