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allywhite666
Posts: 66
Registered: ‎01-01-2014
Message 1 of 11 (311 Views)
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Surface boundary problem

311 Views, 10 Replies
01-09-2014 06:06 PM

I have this surface that I have created

1.jpg

 

I drew a polyline around the site then added a boundary with a destructive break line because there were points outside the line I want to ignore but this is what I got.

2.jpg

 

You notice there are parts missing from the surface anyone know why it does this? Below is a zoom in on the bottom section that is missing.

 

3.jpg

 

I realise that I can do it with non-destructive boundary see below but why is it doing this, anyone know?

 

4.jpg

 

Any help is appreciated.

*Expert Elite*
sboon
Posts: 2,067
Registered: ‎11-08-2005
Message 2 of 11 (287 Views)

Re: Surface boundary problem

01-09-2014 09:51 PM in reply to: allywhite666

A destructive boundary "destroys" any TIN triangle that crosses it - removing the entire thing.

 

In this case you may want to use a non-destructive boundary, which works more like the ACad TRIM command - clipping the existing TIN triangles at the boundary and then connecting the end points with new lines to form new triangles.

 

Steve
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Valued Contributor
allywhite666
Posts: 66
Registered: ‎01-01-2014
Message 3 of 11 (283 Views)

Re: Surface boundary problem

01-09-2014 10:00 PM in reply to: sboon

But non-destructive will include all the points outside the boundary. There are two triangles it should have created in the example below.

 

1.jpg

*Expert Elite*
sboon
Posts: 2,067
Registered: ‎11-08-2005
Message 4 of 11 (277 Views)

Re: Surface boundary problem

01-09-2014 10:13 PM in reply to: allywhite666

But non-destructive will include all the points outside the boundary.


Nope - The new surface edge will stop at the non-destructive boundary. 

 


There are two triangles it should have created in the example below.


The software will not re-triangulate after adding the boundary to fill in the missing edges.  If you really want a TIN line from 222 to 228 then you need to add that after the boundary.

Valued Contributor
allywhite666
Posts: 66
Registered: ‎01-01-2014
Message 5 of 11 (276 Views)

Re: Surface boundary problem

01-09-2014 10:15 PM in reply to: allywhite666

Ok I figured it out, the outside points were causing the triangles to run outside the boundary. So I put a break line round the boundary first then set the boundary. Thanks for the help

. :smileyhappy:

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sboon
Posts: 2,067
Registered: ‎11-08-2005
Message 6 of 11 (271 Views)

Re: Surface boundary problem

01-09-2014 10:19 PM in reply to: allywhite666

Another solution which may work better - offset your current boundary polyline slightly, 1-2 cm outside of your intended surface edge, and then apply that new polyline as a destructive boundary. 

 

Steve
Please use the Accept as Solution or Kudo buttons when appropriate

Valued Contributor
allywhite666
Posts: 66
Registered: ‎01-01-2014
Message 7 of 11 (269 Views)

Re: Surface boundary problem

01-09-2014 10:27 PM in reply to: sboon

@sboon

"

But non-destructive will include all the points outside the boundary.


Nope - The new surface edge will stop at the non-destructive boundary.

"

This will not work you have to put the break line in to make the triangles run along the boundary or it will include the points outside the boundary and distort the contours see below. The circle shows the errors.

 

non-destructive break lines.

 

2.jpg

 

Destructive boundary with break lines.

3.jpg

 

It smoothed the errors.

*Expert Elite*
sboon
Posts: 2,067
Registered: ‎11-08-2005
Message 8 of 11 (261 Views)

Re: Surface boundary problem

01-09-2014 10:38 PM in reply to: allywhite666

Can you post a copy of the drawing?

Valued Contributor
allywhite666
Posts: 66
Registered: ‎01-01-2014
Message 9 of 11 (251 Views)

Re: Surface boundary problem

01-09-2014 10:50 PM in reply to: sboon

No problem Steve.

*Expert Elite*
sboon
Posts: 2,067
Registered: ‎11-08-2005
Message 10 of 11 (232 Views)

Re: Surface boundary problem

01-10-2014 12:31 AM in reply to: allywhite666

I wanted to try something else, but that didn't work so I did some messing about to show some other things which can improve your workflow and possibly make life easier in future.

 

I've added string numbers to some of your points that represent linear features, like fences and edge of roadway.  I edited your Description key and added wildcards to those keys so that the numbers are recognized as part of a legitimate description.

 

I added your drawing points to survey database and built a Figure Prefix database to create survey figures that connect the points with string numbers.  Unfortunately the FP database doesn't allow wildcards but it's easy to copy and renumber them.  Some of the figures are 3d breaklines, while others build 2d lines only.

 

Clipboard01.png

 

If you add string numbers to your field coding then you will be able to "draw" the lines as you work, and you can automate the drafting and surface construction.

 

Steve
Please use the Accept as Solution or Kudo buttons when appropriate

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