Gears and sine waves and things

 From: keith1961 (KEITH) 21 Aug 2010  (1 of 7)
 I thought there would be loads of stuff on how to do what I am attempting but I cant find anything. How do I chop the top off this cylinder in a manner that leaves a clear sine wave all the way round. I have projected some curves and tried both circular array and rail revolve but I cant get the end points to align. Even if I could achieve this goal it still isn't clear to me how I could chop the top off. I am guessing I could rail revolve a surface to separate the top and bottom of the cylinder. Any suggestions? Thanks Keith Attachments:

 From: Marc (TELLIER) 21 Aug 2010  (2 of 7)
 Hi Keith, Maybe cutting the cylinder at the quadrant of the curve, then Boolean merge and array? Marc Attachments:

 From: steve (STEVE_HOME) 21 Aug 2010  (3 of 7)
 3730.3 In reply to 3730.1 Hi Keith As you have the curve projected to that outside surface, separate the tube and delete the inside/top/bottom faces, then use that projected curve to trim off the top of that outside surface, then use shell. - Steve EDITED: 21 Aug 2010 by STEVE_HOME

 From: Michael Gibson 21 Aug 2010  (4 of 7)
 3730.4 In reply to 3730.1 Hi Keith, > Even if I could achieve this goal it still isn't clear to me how > I could chop the top off. Well, if you can get a curve that is projected on to the outer surface of that shape, then you could delete the other surfaces and then trim the outer surface with the curve to slice off the top part, then use Shell on it to thicken that trimmed surface into a solid. But it may be easier to try and construct a cutting surface. You mentioned using rail revolve, but instead you may want to use Loft on a radial pattern of lines. For example here I used Transform > Array > Circular to duplicate a line in a radial pattern, then moved some of the lines up and then used Loft (with the closed option checked) to build a surface through them. Once you have that surface created, you can then use it as the cutting object in Boolean difference to slice your solid into 2 pieces and delete the top part. - Michael