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Advice regards curve fitting - splines?

IO
Ian Oliver
Wed, May 31, 2017 2:25 PM

On 2017-05-31 12:23, Parkinbot wrote:

Good plan. It will work.

Yup, 100 lines of code and changing control points (only 4-5 so far)
changes shape, roundness, and if you go <1 for superellipse factor, you
get rockets for free!

On 2017-05-31 12:23, Parkinbot wrote: > Good plan. It will work. Yup, 100 lines of code and changing control points (only 4-5 so far) changes shape, roundness, and if you go <1 for superellipse factor, you get rockets for free!
IO
Ian Oliver
Sat, Jun 3, 2017 11:52 AM

On 2017-05-31 12:23, Parkinbot wrote:

  1. use nSpline() to interpolate the rows.

nSpline is working well and I'm using it for all of my open Splines. Can
it handle closed ones? I have another spline lib (tjw-spline) doing that
currently but if I can just use one library ...

I'm now mostly working with big bunches of points that I transform and
skin. The tail on this FireFlash is formed from three sets of sixteen
control points from a wing profile function, one set of these is then
"dropped" onto the body points using a recursive closest point search, I
then use nSpline to get many times more points running up the structure,
tjw spline to get closed loops, and then skin the lot. Lots of splines,
and fair bit of matrix maths/transpositions, and plenty of fun!

Original control from function = red, nSpline interpolated points =
white, final skin points = black. This is the low res viewing version.

On 2017-05-31 12:23, Parkinbot wrote: > 3. use nSpline() to interpolate the rows. nSpline is working well and I'm using it for all of my open Splines. Can it handle closed ones? I have another spline lib (tjw-spline) doing that currently but if I can just use one library ... I'm now mostly working with big bunches of points that I transform and skin. The tail on this FireFlash is formed from three sets of sixteen control points from a wing profile function, one set of these is then "dropped" onto the body points using a recursive closest point search, I then use nSpline to get many times more points running up the structure, tjw spline to get closed loops, and then skin the lot. Lots of splines, and fair bit of matrix maths/transpositions, and plenty of fun! Original control from function = red, nSpline interpolated points = white, final skin points = black. This is the low res viewing version.
P
Parkinbot
Sat, Jun 3, 2017 5:01 PM

Nice to read that nSpline() is fun to use. Sorry, I have not yet implemented
closed splines. Shouldn't be to difficult, but I never found time (and
reason) to go into that quite old piece of code again. It was my first
serious OpenSCAD project and I remember that I really damned the language
design of OpenSCAD functions that time.

--
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Nice to read that nSpline() is fun to use. Sorry, I have not yet implemented closed splines. Shouldn't be to difficult, but I never found time (and reason) to go into that quite old piece of code again. It was my first serious OpenSCAD project and I remember that I really damned the language design of OpenSCAD functions that time. -- View this message in context: http://forum.openscad.org/Advice-regards-curve-fitting-splines-tp21597p21637.html Sent from the OpenSCAD mailing list archive at Nabble.com.