I model the attached part using a vary sketch feature, since I need it to be 100% parametric (the part is configured inside the Design Table which opens as a part configurator.  The part works OK if we model the rings to be circular, however, we need the same type of fan guard with all the "rings" to be made with polygons (linear sections between the radials, as show on the first and last "ring"), the problem is that after modeling the first middle ring and pattern it to populate the guard with as many rings as reqeuired to obtain the desired separation between them, the radious of the "bends" at the corners growth (see the picture), and we need those bends to have the same radius (0.5" at the axis of the wire).

Any one know how this can be done in SW?

The part need to be parametric and work with only the inputs show on the "configurator" (inside the Design Table).  In the real asembly those values are "passed" from the product configurator, directly into the design table, so the fan guard automatically fit the fan on the machine (on any size from 12" to 86", or larger).

The attached ZIP file contain the part done in SW 2009 sp 4.1

We can not found a solution to this problem, and to model each ring in place for each fan-guard will be a big problem.  We do this for long time with circular rings, but now someone have the greath idea of wanting the fan guard to look like a spyder web (he is the boss, not spyderman).

Thanks in advance for any help.