Importing Topographical data

[Anonymous]

There are lots of times when the designer needs to design a building in an area where the terrain is not flat. What I would like to know is whether or not Archicad 20 is capable of importing files with this type of data. And if so, in what format should the file(s) be in. It would be even better if Archicad was capable of importing this type of data from Google Earth. My current process is to save a picture from Google Earth which I then merge into Archicad and scale it so it provide a 1:1 scale. This is great for locating the building on the site but it lacks the necessary terrain data. Any info on how I might be able to add the terrain data is greatly appreciated.

Mike

[rgarand]

Tried your suggestion. The magic wand settings do not seem to have an effect either way, I tried multiple settings and multiple increments.

I am thinking it may have something to do with the original polyline. If I draw a spline from scratch, the magic wand will realize when there is a longer, straight segment and will not place any extra nodes/points.

Anyway, I appreciate your suggestions and comments.

[Richard Morrison]

There are a couple of things you might try. (I know the method works. And it's not mine, just something I've picked up over the last twenty years or so.)

1. Try unifying the polyline first, if you need to. You should be able to get the polyline selected with one click. It can have a bizillion nodes. If it doesn't unify, then your surveyor may need to use continuous lines rather than a dashed line.

2. Create a spline from that polyline by using the magic wand. Use "best fit" with a small deviation. The spline can have a bizillion nodes, too. You only care about creating a single spline for each contour line.

3. Change the magic wand to "linear segments," with a segment length of 10', say.

4. Now select the terrain with the splines visible. (Terrain tool must be active.) When you magic wand the spline the "New Mesh Points" dialog should pop up. When you click OK (with "fit to user ridges") you should get nodes spaced at 10' along the spline. Then click on one of the nodes to get the "Mesh Point Height." (make sure that "Apply to All" is checked.)

This goes much faster than the description.

[DGSketcher]

Thank you Richard, works for me. I just received a survey with a "bizillion" nodes per contour, now I can get on and produce a realistic terrain. Last time I had this I resorted to creating the mesh with the plan spot heights to keep the node count down, which generated a less than smooth surface combined with a few odd bumps & dips.

[Brad Elliott]

The key to this is that it DOESN'T work with the SPLINE tool but DOES work with the POLYLINE tool.
Don't ask me how I spent my Saturday.

[Chris Grantham]

The one issue i have with the technique is that there are some areas that require a bit more resolution then others.

If I set the linear segments to say 5' i get way more points i would need in some areas, while not nearly enough where the topography becomes more complex.

[R Muller]

Richard, I tried your method and it works well for the site survey information. Now I am trying to add the surrounding neighborhood, and running into a lot of problems.

I am trying to import information from a large DEM (USGS Digital Elevation Model) file with 2' topo of the entire county. I had someone make me a .dwg file out of it, which has about 350 polyline contours. I exploded one and discovered it has over 57,000 segments. The .pln file is about 110 mb.

I want to cut away the area I don't need, so I can reduce the file size to something less sluggish, and make my neighborhood mesh from the relevant area.

However, I have not been able to split any of these polylines. Any ideas why not? I am not used to working with 2D stuff, so maybe I am missing something.

Help! I have a deadline coming up and haven't even begun to do anything useful with this information.

[R Muller]

Did some more experimenting. Polylines that have 16,000 or fewer segments (as defined by exploding the line) can be split, while polylines that have 25,000 or more segments cannot be split. Seems like a bug.

However, even the larger polylines can be magic wanded into splines, and the splines can be split. Seems like a work-around.

[Richard Morrison]

R wrote:
Did some more experimenting. Polylines that have 16,000 or fewer segments (as defined by exploding the line) can be split, while polylines that have 25,000 or more segments cannot be split. Seems like a bug.

However, even the larger polylines can be magic wanded into splines, and the splines can be split. Seems like a work-around.

I probably would have tried:

1) exploding the polylines;
2) creating a marquee slightly larger than the area I wanted;
3) Doing a Find & Select OUTSIDE of the marquee and deleting those segments.
4) Re-consolidating the line segments into polylines.
5) Proceeding with the terrain, as usual.