Line perpendicular to curve or spline

[cadman6735]

 

Hi all, I am looking for a little help. (actually a lot of help)

I opened my big mouth and promissed something I can't deliver upon, if I can't deliver no big deal only my ego is damaged.

 

I have a colleague in the civil department who goes thru this long and daunting process to draw parking lot spaces on curves and I think splines too (only make sense that splines woudl be included) it even makes me cringe watching him do this process. Well my skills are limited to variable and some setting changes that help me do my job, but my pain for this guy and my ego said "yes" I can help you. (this was about 2 months ago now)... I don't have the first clue where to start and my work load has me brain dead on even getting excited to figure it out.

 

Basicly what I am looking for is this:

select a curve or spline and it will ask for user input (A) and (B) see image and depending on which end of the arc/spline the curser is it will start to create the line starting at the endpoint and stop when user clicks a point somewhere on the screen or continue to the end of the arc/spline if curser moves past the other end point of the arc/spline.

 

I have googled and checked out LeeMac's site and found close to what I am looking for but nothing I can manipulate.

 

If someone could help me with this all I can say is a big thank you and if not, well it didn't hurt to ask.

 

Thanks in advance

[Lee Mac]

The vlax-curve-* functions are your friend.

 

Specifically, use vlax-curve-getpointatdist to locate the points on the curve which are at a specified distance apart (B), and use vlax-curve-getfirstderiv coupled with vlax-curve-getparamatpoint to get the tangent vector at a specific point.

 

With the tangent vector you can get the perpendicular vector and locate a point at a specified distance along this vector (A).

[cadman6735]

very good, thanks lee

I also just found this thread under similar:

http://www.cadtutor.net/forum/showthread.php?55398-lines-perpendicular-to-spline

 

I think I can figure it out from here

 

Thanks

[Lee Mac]

If you have access to 2012, this could also be achieved using the Path Array.

[cadman6735]

If you have access to 2012, this could also be achieved using the Path Array.

 

 

Well flip, Path Array is the answer

 

Thanks Lee

[BIGAL]

I would like to meet a concrete contractor that could build accurate splined kerbing I would take a look at how kerbing is built and how few points are used to construct it by them . True rad - rad is achievable spline ???

[Lee Mac]

For those who don't have access to 2012 and the Path Array, another method would be to create a block from a vertical line of length (A) and use the Measure command to space the block along the curve with a segment length of length (B), aligning the block to the curve, then explode/purge the block when finished.