Best way to export mesh or 3D topo from AC22 to GIS?

[R Muller]

I am working with someone who needs to pick up my grading design and put it into his GIS system to analyze the impact of construction acoustics. He says he can't use my mesh because it has too many triangles as saved into a 3D DWG. I have a layer of 2D polyline topo lines as well as the mesh, but don't know of any way to assign an z-elevation to these lines and he can't use them without an elevation. There are about 100 topo lines.

Does anyone know of an easy way to give him what he needs? Is there such a thing as a 3D polyline in AC22?

I can imagine creating 100 slabs, one for each topo level (easy to do with a multiply command), and intersecting them with the mesh to create "3D contour lines". Is there a better way?

[Barry Kelly]

R wrote:
Is there such a thing as a 3D polyline in AC22?

The only type of 3D line in Archicad is a Morph line.
I'm not sure if that will help you though.

Barry.

[Erwin Edel]

Too many triangles just means the mesh is too big or too detailed (or both).

Maybe copy your mesh and make it smaller (if you have a very large area and can make do with a smaller one).

You might be able to convert it to a morph and modify the segmentation to have less segments, though at this point you might lose accuracy where you do not want it.

3rd way is to create a new mesh by overlaying a grid on the topo lines and setting the height of the individual grid points according to the nearest topo line. You will get a simplified mesh, if you make the grid big enough.

You could make the grid denser in areas of more detail.

[R Muller]

Thanks for your replies. I'm just getting back to this, this time going with an IFC translation. I have had some issues with upgrade of my model into AC22 (it started in AC 20) and have been working to get a fuller upgrade of Classifications and other attributes. At this point, I think I have updated everything having to do with the meshes fully into AC22. Here's what I think I know:

1. Meshes can be defined per the standard ArchiCAD Classification 22 as either "site geometry" or "building element proxy". It seems to make no difference in the IFC translation, which translates the mesh into an object either way. Is there any other option that I have missed?
2. Re: the representation of triangulation of meshes in AC22. If "show all ridges" is selected in the Floor Plan mesh settings, AC22 2D plan view now shows the used defined ridges in the "uncut line pen" color, while generated ridges are shown in the "ridge pen" color. This gives a good visual confirmation of user defined vs. generated ridges. However, in 3d views, user defined ridges show (in the "uncut line pen" color, not the "ridge pen" color) if Contours are selected in the 3D Style. Generated ridges don't show at all unless "all ridges sharp" is selected in the 3D mesh settings, in which case they show the same color as the user defined ridges in the "uncut line pen" color, not the "ridge pen" color. The floor plan "show all ridges" setting has no effect on the 3D view. I find the colors used to show ridge pens to be inconsistent between 2D and 3D as well as using confusing terminology. Is there some logic here that I haven't grasped? I am checking this because it may affect the results when this mesh is translated to IFC, as discussed below.
3. In the translated IFC file, opened back into ArchiCAD, all ridges show in 3D and all are in the same color. The 2D view does not show user defined ridges. Thus the person getting this file has no way to see my user defined ridges (the contour lines) as distinguished from other ridges. Is there a way to set the translation to distinguish the user defined ridges from the other ridges?
4. Is there any other way to include the topo lines in the IFC file? Polylines don't get included...