topic Re: Divide a curve into equal x axis segments in AutoCAD Forum

Divide a curve into equal x axis segments

Anonymous — Tue, 01 May 2018 08:08:59 GMT

Hi All,

I will like to measure a spline into using equal spaced divisions based on a ruler located on the x axis.

Measure and divide command space equal along the spline only. see image. The top is using measure command. but I actually like to achieve the bottom effect. Is there a way this can be achieved on any curve?

Thanks

Re: Divide a curve into equal x axis segments

imadHabash — Tue, 01 May 2018 08:46:51 GMT

Hi,

>> Divide a curve into equal x axis segments <<

as i understand that you want to get equal horizontal ( x ) spaces from equal divided curved spline .... i doubt that it could be !!

Regards,

Re: Divide a curve into equal x axis segments

Anonymous — Tue, 01 May 2018 09:21:20 GMT

That will be two conflicting task. The divisions along spline cannot be equal.

Re: Divide a curve into equal x axis segments

Kent1Cooper — Tue, 01 May 2018 13:50:59 GMT

That can certainly be done with an AutoLisp routine. It would be a matter of stepping along the X increments, drawing a temporary vertical Line at each location, finding where it [virtually if not actually] intersects the Spline using the (intersectwith) method, and drawing a Point on the Spline there.

Tell us more about initial conditions and steps. Is there a Line drawn horizontally at the bottom already? Do you want that Line and the vertical ones left in the drawing in the end, or are they only temporary for determining the locations of the Points? Is it to be more like Divide or Measure in the spacing in the X direction? Is that to be calculated from that base line [if it exists], or specified by the User? Etc., etc.

Re: Divide a curve into equal x axis segments

leeminardi — Tue, 01 May 2018 14:11:37 GMT

Extend the red lines so that they go past the spline.
Make a copy of the spline and the red lines a known distance away from the original.
Give the trim command and select all the vertical red lines in the original and the copy.
Hit Enter and then click on the 1st, 3rd, 5th,... segments of the original spline as well as the 2nd, 4th, 6th,... segments of the copy of the spline.
Move the spline segments from the copy back to their original position.

Re: Divide a curve into equal x axis segments

Anonymous — Tue, 01 May 2018 14:39:12 GMT

Sorry I am using AutoCad LT 2014

Re: Divide a curve into equal x axis segments

Kent1Cooper — Tue, 01 May 2018 17:09:40 GMT

@Anonymous wrote:

Sorry I am using AutoCad LT 2014

Than you'll probably have to draw a vertical Line and Array it or something, and manually place the Points where each one intersects the Spline [as I imagine you did for the second image]. I don't think there's any way to get that result any more directly with ordinary AutoCAD commands, so without AutoLisp capability you're stuck.

[It's always a good idea to indicate that you're using LT when posting a question, since in so many cases it has such an affect on the solutions people can suggest.]

Re: Divide a curve into equal x axis segments

ChicagoLooper — Tue, 01 May 2018 19:38:04 GMT

If you would like to "measure a spline into using equal spaced divisions based on a ruler located on the x axis" then you are technically not measuring the spline. You are actually dividing that portion of the x-axis directly below the curve, or mathematically (X2-X1) / 14 = Y. Where Y= the distance that will provide 14 equally spaced sections under the curve when measured along the x-axis.

Since your parameter requires the spacing to be equal when placing a ruler on the x-axis, using the 'DIVIDE' or 'MEASURE' command on the curve will give erroneous results because the slope of the curve varies from section to section. If we use geometric principles and apply the Pythagorem theorem (where A² + B² = C²) you are only interested in the x-component of each section and don't care about the y-component.

There are many ways you can accomplish this in Cad. Using SCALE and OFFSET commands is just one way.

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Re: Divide a curve into equal x axis segments

Anonymous — Tue, 01 May 2018 20:25:54 GMT

I will attempt using scale and offset as suggested by ChicagoLooper

when I return to work tomorrow. If it works I will post the solution.

Thanks