Site Model from Contours - poor automatic surface creation

[Poot]

Hi Everyone,

 

I'm having a problem where creating a site model from source contours is changing those contours for reasons I cannot understand. (source file attached)

 

As you can see below, I have worked out all the contours so there where the details should be OK (early stages here).

 

However, one corner for example is giving me problems for unknown reasons.... You can see below that the contours are drawn cleanly where there is a sharp rise (wall basically)

 

Yet when the surface is generate from these contours, it does some very funny things that totally change these contours.

 

 

 

I have tried several options like adding in some extra 3d geometry, grade modifiers afterwards on the proposed site, which gets closer, but there is quite a number of large artifacts that aren't always explained (some are usually my error)

 

Am I missing something here?  I could in Theory try using all of these contours again as site modifiers, but that seems a bit odd....

 

Example.vwx

Edited July 16, 2021 by Poot

[Jeff Prince]

@Poot I took a quick look at your file.

 

Here are the problems...

Data is dirty...overlapping 3D polys.  Run the Validate 3D Data command to see where your problem children are hiding.  Delete them.

Using contour data with too many vertices.  I do not know where you go your contours, but oftentimes it is better to start with point data and let Vectorworks develop contours for you.  Oftentimes, this results in superior contours.  If you are going to use contours such as these, Simplify 3D Polys is your new friend for reducing these contours to something more manageable.  Remember, contours are just some software's guess, based upon point data, as to where a surface elevation is.  When you take someone's guess and have Vectorworks generate a new guess, you get deviation.

 

Just deleting those overlapping polys makes a big difference....

 

 

Increasing your Crease Angle and contour interval yeilds nice results after the data is cleaned.

 

Hope it helps.

 

 

[Poot]

Thanks for the tips! I was pretty sure the problems were all on my side...

I understand the points on simplifying polys. They are typical for source contours we receive during the start of a project, or generated in Civil from a surface. 

 

I'm the only one in the office working with VW at the moment, so my workflow involves bringing drawings over from AutoCAD/Civil into VW for 3d modelling, BIM, etc.  I am in the process of figuring out the simplest way of doing this, which of course would be largely solved if starting work in VW directly.

 

Edited July 16, 2021 by Poot

[Jeff Prince]

3 hours ago, Poot said:

I'm the only one in the office working with VW at the moment, so my workflow involves bringing drawings over from AutoCAD/Civil into VW for 3d modelling, BIM, etc.  I am in the process of figuring out the simplest way of doing this, which of course would be largely solved if starting work in VW directly.

Starting in Vectorworks doesn’t solve your problems, having a managed method of project development does.  That is software agnostic.  Don’t fall for that trap of “it’s easier to use Brand X software for this”.  Vectorworks 3D site and LA BIM tools are fairly primitive at this point.  Not bad, just not where we would like them to be and a bit cryptic to use until you get your sea legs.  I do almost all of my projects in 3D, none of it actually starts in Vectorworks in terms of data collection or initial site drawings.  Sometimes it’s digital from others, sometimes it’s hand drawn by me.

 

Ultimately, your success is determined how well you play with others, especially being the only Vectorworks person within the office.  Develop a strong understanding of the different 3D data types for site modeling, when it is appropriate to use them, and how to request them from others.  Be sure to test how to get your data out of Vectorworks and into what your colleagues are using, before it matters. Just remember, sharing contours back and forth can really screw you up.  They can become as accurate as a sketch that was faxed, copied 3 times, and then rained on 🙂