creating lines of level from points

Hi, can anyone help?

We get a project and we need to create line of levels (line linking points
of same z) from a cloud of points (around 3000).
Any clue how to achieve this?

thanks

 

I'd suggest that you use a scrip like discussed in the thread titled "RE: plot function" Generally what it's saying is get
your data in "X,Y,Z" and use the scrip command "Pline" to connect the first series of points, ect.
R. Wink

 

The only problem is in what order to connect them. I take it that the points
are sitting in space, and depending on the shape of the resultant line, a
routine that looks for the closest point might pick the wrong one and make a
mess of it.

--


MichaelB
www.michaelbulatovich.com

plot function" Generally what it's saying is get

 

Damien, Michael is right. Just running a script or a custom command that
only searches for a common 'z' value would more likely result in a mess.
The programming to do this can become quite involved and would require the
use of something towards the like of Delaunay's formula that many products
use for generating tins and contours.

One of Autodesk's partner products might have something you are looking for.
Because the autodesk website has to be one of the worst for navigating in
existence, here is the link to get you to the partner product area.

http://partnerproducts.autodesk.com/catalog/default.asp

Hope you can find something.

TimB

 

You know....at a click per second, 3000 clicks is under an hour. If this is
a one-time problem for the OP, a simple lisp could color-code points at a
particular Z elevation for easy recognition and someone could connect them
in a couple of hours. Now that I think about it, if this will do, the filter
and change commands might be the quickest way. Just crank up the stereo
really loud, put on some fun repetitive music, and get clicking.

 

snip

.... and get ready for carpal tunnel therapy But to add to what you
mentioned.... if the routine placed the differing 'z' valued points on
separate layers, the user would be able to segregate the points further, and
make the selection easier. If we keep this up, we will be able to hash out
the complete logic and end up with the programming model for it... L.O.L.

Take care Michael,

TimB

 

Bonjour,

Peut-etre ici: http://www.delicad.com/autocad/flashcdn.htm

Philippe

damien a écrit :

 

Philippe, went there... some nice stuff! It might do what Damien wants, but
he seems to be looking to simply connect points of the same elevation.
Generating contours via a tin will not necessarily give him that, as the
lines created would be based on requested elevation intervals.

Take care,
TimB

 

What's a "tin"?

 

Hell, it's been so long that I used anything but the term "tin". If I
remember right, and don't count on it, it stands for Triangulated Irregular
Network. Basically you have a bunch a points with elevations scattered all
over in no specific order. The DTM (digital terrain modeller) will take all
these points and using algorithms and such, make sense of the mess and draws
a bunch of triangles from sets of three points. Basically after the first
triangle is determined, the old 'take two from the old and add one' is used
to form the next set of three points and so-on. You end up with a bunch of
closed 3d pline triangles that do not overlap to represent the surface - and
from there... bla bla bla

Not much of an explanation, I know, but it should give you the idea.

Take care,
TimB

 

thanks everyone.. we surely get something out of this!

 

No, that's great. I got it. Thanks.

 

Sorry, I kinda went over the top on that one. It kinda happens when you
drink way to much coffee and munch on chocolate covered coffee beans at the
same time. Cripes, I don't think I'm gonna get to sleep until next tuesday.

 

why not look at the points side ways on by changing the viewpoint.

select groups of points that are similar in Z value. and change there
colour or change there layer.

with the points seperated out into groups that are similar Z value, 3D
polylines could be used to join up series of points to create
approximate contours.

*)import the 3D polylines into 3D studio Max.

*)apply a terrain compound object to the group of 3D polylines and you
get a TIN.

*)export the TIN back into autocad. lets pretend the TIN is a mountain
range and colour it brown.

create a big flat plane under the TIN. This will be our water level,
colour it blue.

move the big flat plane upwards asif the water level is rising.

If you look down on a shaded view of the mountain range as the water
rises, the countours will appear at the boundary of blue ocean and
brown mountain. trace over the contours with ordinary flat polylies.


* find a friend with 3D studio max. These three steps would take about
5 minutes to do.

option 2 buy some expensive land surveying software.