Can anyone help me understand How to create a station points along a polyline with varying offset from given alignment.

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Are you just using Autocad?

Yes sir, I'm using autocad civil 3d, I tried creating points thru measured alignment but it applies only if the polyline is parallel to the given alignment.

Why not just make a scratch alignment out of the polyline and then hide or freeze it after you have set your points?  Or are your stations based upon the given alignment?  I think I understand your problem.  You want points at stations that are based upon an established alignment, but your points are more easily created as offsets from another pline that is not parallel to the given alignment.  Is this what you want to do?  I think you might need to first set points along the pline at the stations (per the alignment) you want to use.  Then turn the pline into a dummy alignment and determine where those points fall with respect to the stationing of the dummy alignment.  Then you could use the new stations to establish your points and then reference them to the given alignment.  I don't know if this helps, but it is just an idea you might explore.  I'm not sure if Civil 3D will let you do that, but Inroads will, so long as you make graphical objects out of the points and import them while the first alignment is active.  I would assume that Civil 3D could manage a similar operation.

I guess it is important to know whether either the alignment or the pline are curved because then things get more messy.  If they are both linear, simple functions could be derived to translate stations and offsets between the two entities.  Linear algebra, anyone?

Reeeally need to know if you are in plain jane Autocad or have some kind of cogo software app added in.

There are several ways that come to mind pretty quickly, but all depend on what software you have.

Sorry I couldn't help more

kevin

Civil 3D?  Terramodel?  Inroads?  What are you using to create your alignment?  I assume you are using a curved alignment.  If not, you can just setup a coordinate system with 0,0 at one end of the polyline and then align the UCS along the x axis.

If it is curved, and if you are using generic AutoCAD, you will either have to go through some fairly tedious commands and set your points one at a time, write your own visual lisp or arx routine, or you will have to find another add-in to do it.  There is no convenient command native to AutoCAD for doing what you want.  If you have maintenance from Autodesk, there are some 3rd party applications available on their support website that will do it.

There is a way to do it in Carlson Survey.  Create a centerline, then check "Locate Offset Points" and "Use Polyline" in the offset setup.

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