Summit or valley curves (Square Parabola)

[venkat241]

Dear All,

 

Is there any lisp program which can fit a vertical curve (Summit/Crest or Valley/Sag curve) between two grades (by selecting two polylines grade1(g1) and grade2(g2) and by giving input as vertical curve length(L) or Radius of vertical curvature (R or K-value).

 

Advanced Thanks & Regards

 

M V Rao

[CarlB]

Well you can draw it without lisp. A parabola for a vertical curve can be represented by a quadratic b-spline.

so you can draw a polyline from vpc to vpi to vpt, set SPLINESEGS to a value for desired smoothness, set SPLINETYPE to 5 (for quadratic b-spline), then PEDIT the polyline, "spline" option.

[eea123]

I've been looking for a plain CAD solution to this as well. So far I found tip1479 at Cadalyst, http://cadtips.cadalyst.com/curved-objects/vertical-curve, but it does not draw the information or profile to the screen. More of an online calculator, but does appear to generate an output file (I can't locate where it is written to).

 

The other is at Fred Weaver's site, http://fredweaver.biz/index.php?option=com_content&view=article&id=23&Itemid=19. I just came across it this weekend and had to roll back the seed DWGs to v00i. I still haven't had it plot a vertical curve, but I get a grid and VPIs plotted. That is likely my use of v00i rather than a bug in his LISP file though.

 

Between the two of these offerings I think we' have a good subistute in plain CAD.

[motee-z]

here is a lisp to draw vertical curve and calculate slope

vertical curvedr.LSP

p04.dwg

[eea123]

Motee-Z, thanks for the posting. I'm getting a few quirks with v00i, but that seems to be with the file version of p04.dwg. I tried rolling it back with DWG TrueView but still get an error.

[eea123]

Motee-Z,

 

We'll I figured out my v00i DWG translation issue, but it looks like I'm still having some minor issues. I'll PM you.

 

Thanks.

[motee-z]

make a drawing in your cad version just draw a triangle and a circle inside name it p04 and replace it with my drawing