# how to pattern a cut-loft around a helix

I'm trying something fancier.. hopefully it will be clear from the screen-shot.. linear and circular patterns work. now, however, I'd like to spiral the cuts. first try isn't working.. it gave me an error at one point, but I didn't comprehend it, and it hasn't shown up again.

here is a second screen-capture presenting the problem. I try to select the outside of the cylinder as the surface that the pattern should be normal to, and it doesn't work..

partial solution: I tried the following (somewhat lame, it gave me no sound?) tutorial and this time it worked: https://www.youtube.com/watch?v=X9xSMBdqcr4 . two things I've learned: the first one.. is rather trivial but irks me for some reason. a helix can't be created from an existing sketch, you have to create a fresh sketch just for it. this seems.. wasteful of time and effort, particularly considering the second thing I've learned: in order for the curve driven pattern to work, the helical path -must- be on the surface to which the object to be patterned is to be normal... so the question would become, why is solidworks built this way. is there a reason for it, or is it just an oversight? :-)

• Tried doing the lofts as unmerged solids rather than cuts, patterning the bodies, and doing a combine/subtract at the end? Feb 5 '20 at 6:54
• You could always make this effect from a series of linear and circular, too. Feb 5 '20 at 9:17
• @JonathanRSwift series of linear and circular? ... you really think that's possible? Feb 5 '20 at 12:59
• "Tried doing the lofts as unmerged solids rather than cuts, patterning the bodies, and doing a combine/subtract at the end?" -nope. I haven't. thanks for the thought! Feb 5 '20 at 13:01
• I only suggested it since you said that linear worked for you. You could do linear with a spacing equal to the pitch of the helix, Then circular, and then use the move/copy bodies command to raise the bodies up to the level of the helix (lift by fractional height of the helix pitch relative to the number of degrees rotated) - this is a very messy way, but it would work, and without having the file it's always hard to diagnose why your curve driven pattern (which is certainly a better method) isn't working. Feb 5 '20 at 13:02