Update DEM or elevation data

[BrianLomas]

Is there a way to update/change a DEM file or some kind of elevation layer which I could use as a terrain? Basically, I have a DEM which has current elevation and I have a 3d multipatch polygon which represents a road that will be built. The road construction will change the landscape which is represented in the multipatch polygon. I need the elevation of the multipatch to be represented in the terrain as well as the surrounding areas current elevation. I hope that makes sense.

I included a picture and you can see where the road is intersected by the terrain. Thanks for the help.

[DanPatterson_Retired]

if it is a visual thing, then you can simply use an offset from the dem once you done the draping it.  This works quite well in most area when placing 2D vector data over DEM data

[BrianLomas]

This wouldn't solve my problem because if I raise the multipatch is would cause a gap b/w the raster and the road (multipatch) in some places. The multipatch is 3d as well. Thanks for the reply though.

[DanPatterson_Retired]

Another way...

• for all steps set using tools in arctoolbox, set the analysis extent to be of the largest raster,
• set the snap raster to it, and the cell size as well
• export the smaller raster to a new copy (right click, on the layer, data export) which will have the larger extent setting the nodata value to zero
• Add them together