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more problems with splines (#2002)

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Steve.M		#1 Posted : Wednesday, January 28, 2009 1:43:54 PM(UTC)
Rank: Senior Member Joined: 6/18/2008(UTC) Posts: 978 Was thanked: 1 time(s) in 1 post(s)		Hello Tim, I have been attempting to make work_arounds for the problems I have been finding with splines. Unfortunately this as just brought up more problems. pic01 this shows my original Int spline construction, as now expected, the endpoints do not align as required, so, I edited the endpoints for alignment. Pic02 After making alignment, the spline is still not consistent with what I would expect. (I originally though this problem was with 3d splines, not splines on 2d plane) pic03 I decided to trim off the top half of the spline along the horizontal C/line. that brought up the error shown. pic04 I then decided to split the spline and then delete the top half. this led to loss of original curvature on the remaining half of the spline. But I continued on, mirrored the spline, and then use join, but, this then led to further loss of curvature pic05 I have attached the VC file at the point of attempted trim - Steve File Attachment(s): 014.vc3 (17kb) downloaded 5 time(s). Steve.M attached the following image(s): 01.jpg (111kb) downloaded 5 time(s). 02.jpg (116kb) downloaded 5 time(s). 03.jpg (27kb) downloaded 5 time(s). 04.jpg (56kb) downloaded 5 time(s). 05.jpg (95kb) downloaded 5 time(s). You cannot view/download attachments. Try to login or register.


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bobc		#2 Posted : Thursday, January 29, 2009 8:19:46 PM(UTC)
Rank: Junior Member Joined: 6/3/2008(UTC) Posts: 6		Hello Steve Yes the ends of the interpolated spline are a bear to control, and trimming or breaking them can create more problems. I would have used a different approach to create your model. Since symmetry is what you are looking for, I would first create one simple curve using a control point spline (4 points only) at one of the node locations. Next using the mirror tool, flip the shape into all the necessary locations. Then use the join tool to join them into one single control point spline. (see attached file) Doing it is way you are in control of the shape and are not relying on the spline to do its magic. Regards - Robert Chubb File Attachment(s): test shape.vc3 (43kb) downloaded 5 time(s). You cannot view/download attachments. Try to login or register.


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Steve.M		#3 Posted : Friday, January 30, 2009 6:11:16 AM(UTC)
Rank: Senior Member Joined: 6/18/2008(UTC) Posts: 978 Was thanked: 1 time(s) in 1 post(s)		Hello Robert. The spline you have produced is incorrect for an interpolated (or through points) closed spline. check the image. The yellow spline is what is required (and what is produced from the spline points) and can be produced very simply/quickly in other CAD systems I use. I do have a workaround that will give me a result that is acceptable, but I am not looking for workarounds, I am looking for bug fixes. regards, - Steve Steve.M attached the following image(s): 2009-01-30_112811.jpg (41kb) downloaded 5 time(s). You cannot view/download attachments. Try to login or register.


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