Elevation points to contour lines problem

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(Melgendy12) #1

This is a rough image of what I have in dwg. How can I use those elevation points to turn it into proper contour lines? I even tried drawing the lines manually but it’s far from being accurate.


#2

I would use Patch command first to make the surface. Contour command will make contour lines from the surface.


(Melgendy12) #3

I only have the elevation points not the contour lines, and the site is
rather complicated for me to guess how the contour goes. I was thinking of
make a surface then cage editing it to roughly look like the site, then
contour that and use the contour lines to further tweak the site. After
that I can try to patch the lines…but there has to be an easier way


#4

You lack the most basic knowledge of Rhino.


(Melgendy12) #5

Very informative reply, thanks


#6

No, there is not really. Your method outlined above is credible. Your real data points are few and far between, so anything in between them you will basically have to invent. No miracles here. Patch will give you a basic surface with your elevation points - assuming they are in 3D, otherwise you will have to elevate them first. You could add more points yourself if you know about where they should be and what height.

You will need to decide how locally editable your surface needs to be, and give Patch a sufficient number of U and V points to do so. The more points in each direction you have, the easier you can edit locally, but the harder it is to edit globally. You can also use CageEdit, the problem is it will add lots of rows of points where it needs and you risk ending up with a very dense surface.

In any case contours derived from a Patch or other NURBS surface (splines) will be relatively soft and smooth, that’s the nature of the beast. You can edit them later as you like.

HTH, --Mitch


#7

So it seems the easier way, in fact the only alternative to “making stuff up”, is to insist on better topo data from your source.


#8

Well in my experience with suppliers of topo data (architects, city planners, etc.) depending on where you are in the world, is that it’s often just as easy to make the stuff up yourself… :stuck_out_tongue_closed_eyes:


(Melgendy12) #9

thanks alot