Surface hole chopping - Tip and Trick

So for visualisation purposes you need to cut a hole out of your ground or other surfaces so that your design fits inside (also so areas in cut will show).

So the technique here you should always make a copy of your ground to edit rather than the original and also as you may have corridors or gradings targetting that surface.

This is also a static method only, boo.

So in green is my combined surface for all the runways and taxiways 

 

By choosing the surface you choose the 'extract objects'

 

 This option you can extract (displayed) surface style objects to normal AutoCAD objects.  In the case of the border you get a 3d polyline.

In this case we will extract the borders

 

In magenta are all the borders, as you can see aswell as the outer boundary you get all the inside boundaries, hmm useful! see the next tip and trick for what we can do with those.

Create a new surface, I always call them 'Context' as they are a surface for visual purposes and not important to your design. 

 

Paste in your existing ground or surface you want to the outer area 

 

 

Here you simply see a copy of your surface, (yes this one is basic)

 

Then to that surface add your outer boundary as a breakline.

This I like to do so that my outer surface has corresponding points in the surface to my design and so there are no gaps in the surface edges to where they meet

 

The triangles update with that breakline

 

 Then add the boundary 

Choose hide and also non-destructive and select your boundary line again 

 

Now you can see the triangles have disappeared inside the boundary

 

The result of your surface and design

 

Jack Strongitharm