parametric sketch limitation?

[Michiel.Valcke]

Hello everyone,

I'm trying to create a plug cap (don't know how else to describe it) that needs to be parametric so that the basic shape can change from triangular to rectangular, all the way to octogonal. Something that sounds and looks simple enough.

 I started with a sketch hoping that I could build the basic sketch in a parametric way and that the rest of the shape would follow. The only main parameters I would have for the entire part are the number of sides, the radius of the main shape and the radius of the inner hole. 

The sketch looks good, but the entire premise is flawed. because the sketch generates new geometry each time (with a circular pattern feature) the number of sides is changed the extrusion cannot be calculated, and everything after that fails (like the offset around the hole, etc...)

I can think of several ways to circumvent this, but creating multiple basic extrusions and suppressing them each based on the value of the sides parameter, or creating an ilogic rule to override and fix any possible issues each time the parameter changes, or to create individual part files, seem such overkill. As I was hoping to be able to generate the alternative shapes using model states. 

Before I post an idea for a new type of parametric sketch feature that would allow extrusions or other features to persist while it changes shape, I wanted to ask here if anybody has had to do a similar design and how they went about it. Or if they have practical examples that they can share/show?

Thank you all for your time.

[swalton · Accepted solution]

Make a circular pattern of a triangle to generate the required number of faces.

This works for 3 to "n" faces.

[Curtis_Waguespack · Accepted solution]

Hi @Michiel.Valcke , 

It looks like @swalton beat me to it, but here is an example file employing the approach mentioned.

Hope that helps,

Curtis

[Michiel.Valcke]

The solution was staring me right in the face, but I was so focused on the basic sketch shape, that I didn't see it. Thank you guys.