Mesh from 3D contour DWG?

[Thomas Holm]

Talking about curved cliffs...

I just got this 3D contour DWG file from a local planning office.

I imported it as an object. As you can see there are no surfaces, just contours, and they aren't even contiguous.

Now I wonder if anyone's got a good idea on how to make an Archicad mesh out of this?

Or am I better off using the conventional procedure of creating the mesh in plan from the 2D contours?

[Anonymous]

I like to create them from 2d lines, I have never seen 3D contours like that before and wouldn't even know where to start. So, I am no help at all.....

[Anonymous]

What kind of planning office gives you a 3D contour????

[Thomas Holm]

In Sweden, when you want to build something, it's a requirement by law that you draw your site plan on an official 'New building map' that you have to order from the local planning office.

But there are no standards- Every city, county or municipality seems to do their own thing. Most (not all) can deliver them digitally, usually in DWG or DXF format, and some of them have even started to deliver 3D information in various ways.

In Autocad, there are 3D surface entities that Archicad understands, like 3D Face, 3D Polyface or Polygon mesh. Archicad's translator can make 3D meshes out of those.

But this particular county has decided to just deliver level info by drawing contours as a normal polyline with a height value (z coordinate). Perhaps there are Autocad applications that can utilize this in a meaningful way, but I don't know.

Also, If you look at the picture you will see that all the borders and building info on the map (well, almost - it's not consistent) lies flat on the zero z. This means I wouldn't see that if I create a surface mesh from the 3D contours.

To me this looks just like a political gimmick - 'look, we use the latest technology, we can deliver 3D maps' - usefulness isn't as interesting to them. But I may be wrong, I was actually hoping to be, if someone here could tell me how to use this!

[Eduardo Rolon]

IME the Z coordinate is created by the software that civil engineers use to establish the contours and 9 times out of 10 they have no idea the lines are floating in space. The easiest way to create a mesh out of this is to get it into SketchUp and use its mesh command. Though I still prefer the "traditional" linked method.

[Thomas Holm]

Didn't think of Sketchup. I'll try that! thanks!

[Djordje]

Thomas wrote:
Now I wonder if anyone's got a good idea on how to make an Archicad mesh out of this?

Did you try ArchiTerra? I would.

[Thomas Holm]

Well Sketchup didn't cut it. I went into Sketchup Pro 6 and used its Create Sandbox from contours command, and the mesh created looked good in Sketchup, but when saved as DWG and opened as object in Archicad, I found that Sketchup doesnt create any of the entities that Archicad can convert to an Archicad mesh. The file consists of lines and individual triangle surface polygons. It looks OK as a surface but can't be used for SEOs. When exploded, all surfaces vanish, only 2D lines left.

Architerra and I have a severed relationship. I bought it for AC10 but I never managed to make it work for me. It works for itself, on its own terms, but for me it's like fitting a square peg into a round hole. Also, the version update delay, the (for me) incomprehensible manual and the fact that its creations don't work fully without the updated application installed into the current AC version rules it out for me.

So I guess I'm back at square one!

[vfrontiers]

I have always promoted RE-CREATING contours from DWG as their resolutions seemed to always be 1 point every 2 or 3 inches! This will absolutely kill your rendering / 3d window times and is senseless as a topographic map is an ESTIMATION anyway.

Simply tracing the 2d version and adjusting heights would probably take only 30min(or less) on your site. You could probably work the math out to pay for itself in 10 3d views or so.

Using some creative SEO techniques (discussed elsewhere on this forum) will let you cut in roads and pads pretty easily.


My $.02...

[Karl Ottenstein]

vfrontiers wrote:
I have always promoted RE-CREATING contours from DWG as their resolutions seemed to always be 1 point every 2 or 3 inches! This will absolutely kill your rendering / 3d window times and is senseless as a topographic map is an ESTIMATION anyway.

Simply tracing the 2d version and adjusting heights would probably take only 30min(or less) on your site. You could probably work the math out to pay for itself in 10 3d views or so.

My experience too, although some mountainous lots may take an hour.

My additional 2 cents:

With Virtual Trace in 11, it is easier than with ghost stories in prior versions for this kind of thing since the Trace Reference can be a Worksheet with an xref to the dwg, so no need to create a fake story for the dwg or come up with strange layer combos to accomplish your work since the active and trace can have different layer settings.

Also, use a Reference Level (Preferences) so that you can enter your z-heights using exactly the surveyor numbers and not have to do any math in your head. 😉

Nonetheless, it would be nice if there was an easy way to convert the 3D contours into an actual AC mesh. (I've only had one surveyor produce these, and I did go the SketchUp route with it...but it was limited, as Thomas notes, and so I ended up making the mesh myself.)

Cheers,
Karl