Help! SPLINE Nightmare

[madpj7]

Hello,

 

I've been using this forum for years and this is the first time I couldn't find the solution to the problem I'm facing.

 

Background: I'm using SPLINE to trace contour lines in a raster image as part of a final project for a class (due 12/09, 8AM). The hard drive on my laptop crashed so I'm using the university's computer lab.

 

Issue: When drawing a SPLINE, AutoCAD is assuming the curve between each point is a 180* arc, causing my nearly-smooth SPLINE to instead look like a roller-coaster, complete with loop-the-loops. The beginning and end of the SPLINE look like knotted shoestrings. I wasn't having this issue on my home computer, so I'm assuming the problem stems from different SPLINE settings.

 

I'm in a pretty dire situation, so if you have a solution, I'd appreciate if you could call and walk me through the fix (in addition to posting the info here for future reference).

 

-Joe

(703) 307-4011

[CarlB]

I don't know of a setting that may have caused this..

but you may be able to fix it with the SPLINEDIT command, "fit" "tolerance" "0" options.

[eldon]

Is it essential to use SPLINE?

 

I would be using PLINE and trace in short straight lines, and curve fit when finished tracing. You could always convert it to a Spline afterwards with SPLINEDIT.

 

Splines have a life of their own, and controlling the curves can be challenging

[madpj7]

Thank you for your input. Unfortunately, changing those settings didn't make any visible changes. I've attached a screenshot of what it's doing.

 

What I'm attempting is to use SPLINE to generate a fairly accurate curve showing the extents of the grading area, so that I can calculate cut & fill. Any other methods of doing this would be appreciated.

 

Thanks in advance,

-Joe "5 o'clock (AM) shadow" Gorman

 

[lpseifert]

Take a hint, forget splines and use plines; you can use the arc option while in a pline command to add curves and then go back ang grip edit it to make it look right.

[Secretagdan]

Probably to late now, but select the spline for grip points, then drag them where you need them to be. If you have the same problem with the poly line/arcs do the same thing.

[rkent]

Just a shot in the dark, but turn Ortho off, maybe turn off snap, polar, otrack as well.

[rustysilo]

Fyi, using splines is generally a bad practice when working in engineering. It is a rare instance for us to use them here.

 

If you must in this case I'd do as previously mentioned and use pline and then pedit > spline them.

[madpj7]

Thanks for the tips guys, I plined and then splined it.

 

For the engineers out there: if SPLINEs are bad, what do you use for interpolation in situations like this?

[lpseifert]

Polylines... drawing contours isn't brain surgery; an art not a science.

[BOB'27T]

Polylines are what I use for tracing contours off of quad maps, etc. It doesn't need to have splines or arcs. Once you draw the polylines, just assign an elevation and add it to the surface.