Quicker way to draw a border around topo?

[wilsonm2000]

Hi guys

Just wondering if anyone has any clever ways to make the process of manually drawing a boundary around a topo so that you can add it as a boundary in a C3D surface?  Sometimes the topo's we recieve already has a boundary in it, but often, there is not.  So we have to manually draw a polyline around the whole extent of the topo, which can take a long time.

Cheers

Martin

[antoniovinci]

If "topo" means a _MAPIINSERTed raster image , you can explode it twice, getting the 4 borders of the frame.

If the boundary is "drawn" not regular inside the image, you could try to vectorize automatically with the free Wintopo.

[wilsonm2000]

By topo, I mean a topographical survey with 3D contours, breaklines, blocks etc.  Its not an image.

[neilyj666]

The way that I do it is the way I've seen Sinc doing it in a video somewhere:

Create the EGL surface and show the border and triangles

Edit the triangles in concave areas, invalid areas etc etc so that the boundary reflects the area of interest

Extract the boundary and flatten to 2D

Edit the surface definition and remove all edits

Add the extracted boundary into the surface as Outer boundary

Add vertices to the newly added boundary to tweak any erroneous area that may have been missed.

[AllenJessup · Accepted solution]

I think this may be the video you're talking about:

http://www.quuxsoft.com/videos/AddBoundaryToSurface.aspx

Allen

[wilsonm2000]

Great, thanks guys for your help :o)

[neilyj666]

Yes that's the video - main difference is I use a 2D boundary and proximity breakline but exactly the same principle.

Can't think of a quicker way to add an outer boundary with a drawing comprising 3D contours, breaklines, blocks etc...???

[wilsonm2000]

Cool, cheers neilyj 🙂 seems the best option 🙂

[Neilw_05]

Have you tried the LINEWORKSHRINKWRAP command?

[AllenJessup]

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@Neilw wrote:

Have you tried the LINEWORKSHRINKWRAP command?

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I've tried it with points. I got very messy results. If you made a copy of the surface and exploded it down to 3D faces it would work.

Allen

[neilyj666]

You get a very dubious boundary if you don't FLATTEN the 3D faces first. LINEWORKSHRINKWRAP also requires totally enclosed areas and also requires 2D data for best results i.e no crashes... 🙂