Clip 3D polygon where it intersects with raster DEM surface

[CraigFrew]

Hi All,

I thought that what I am trying to do would be relatively simple but it has me a bit perplexed. Basically I have a 3D polygon and a raster DEM. I wish to clip the polygon where it intersects with the DEM so as only the portions of the polygon which lie above the DEM remain.

Any Suggestions??

Craig

[JeffreySwain]

The only 3d portion of a 3d polygon is the edges.  Are you trying to harvest the inner section as well?  If so then I recommend converting the polygon to a Multipatch and then the surface to a multipatch as well. Then you could use the Intersect 3d.  Or if the 3d polygon is at a constant elevation, consider the Surface Volume tool or the Polygon Volume tool after you convert the raster to a TIN.

[AbraKaiser]

How do you turn the surface to a multipatch? I am trying to do this same thing, starting with a DEM. I've turned it into a TIN (which lost a lot of the topography), then used the TIN Triangle tool to make polygons, but then when I tried the Intersect 3D tool I got an error because the multipatches in my surface weren't closed. The Enclose Multipatch tool ended in error after 15 minutes. Is there an easier way to make the DEM into a Multipatch that also keeps the terrain detail?

[CraigFrew]

Cheers, I will give it a shot.

Craig

[JoeChampagne]

Is there any way to perform this 3D intersection between vector (TIN or Multipatch) and DEM WITHOUT converting the DEM to raster?

I'm trying to intersect a surface generated from a long (~1200 km) linear feature with a large effective DEM that's made up of many tiles managed in a Mosaic Dataset.

It seems prohibitive to try to convert either of the inputs due to the effective volume of the raster at full resolution within the bounding rectangle of the project area.

Any thoughts? Thanks!