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Surface boundary problem

10 REPLIES 10
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Message 1 of 11
allywhite666
2952 Views, 10 Replies

Surface boundary problem

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.

10 REPLIES 10
Message 2 of 11
sboon
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
Please use the Accept as Solution or Kudo buttons when appropriate

Steve
Expert Elite Alumnus
Message 3 of 11
allywhite666
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

Message 4 of 11
sboon
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.

Steve
Expert Elite Alumnus
Message 5 of 11
allywhite666
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

. Smiley Happy

Message 6 of 11
sboon
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

Steve
Expert Elite Alumnus
Message 7 of 11
allywhite666
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.

Message 8 of 11
sboon
in reply to: allywhite666

Can you post a copy of the drawing?

Steve
Expert Elite Alumnus
Message 9 of 11
allywhite666
in reply to: sboon

No problem Steve.

Message 10 of 11
sboon
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

Steve
Expert Elite Alumnus
Message 11 of 11
allywhite666
in reply to: sboon

WOW Steve thank you so much for taking your valuable time to do this for me. I have only started using Civil 3D and am slowly building a template so this helps me greatly. It is so different form Land Desktop which I used many years ago.

 

My original plan was to create 2 templates one for points and one for lines for two reasons 1. Tree symbols only have one point style and I wanted a trunk and a spread so I was going to do one in each template and 2. This would mean I can have every layer I could use created, draw my lines, copy them into the other drawing and leave the unused layers behind.

 

Your setup with string lines will help me a lot so I will play around with it and see how it works. Thanks again Steve. <3<3<3

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