topic Re: Extracting Slope Bands in Civil 3D Forum

Extracting Slope Bands

makaosant21 — Tue, 28 Apr 2026 18:39:29 GMT

I currently have a surface from lidar data and isolated a slope range using the slope analysis and slope banding surface style. I selected this surface and extracted the objects and they resulted in 2D Solids (since I set it that way) but there are too many. Each triangle is extracted.

Is there a way to quickly combine congruent areas to create one solid?

The output Im trying to achieve is a plan view KMZ but the filesize and the amount if objects crash the software. Any ideas? https://100001.onl/

Re: Extracting Slope Bands

igi_pop — Wed, 29 Apr 2026 12:48:19 GMT

Hey,

Unfortunatley, if you create a solid from surface, it will still use ALL triangles.
If you extract them, the extrusion is a choke machine.

My recommendation, do this task in a GIS enviroment 🙂

Iggy

Re: Extracting Slope Bands

igi_pop — Thu, 30 Apr 2026 07:16:36 GMT

To give you an idea, here are some screenshots:

DatashadedSlope analisys (50-120%)Google Earth

Re: Extracting Slope Bands

AllenJessup — Thu, 30 Apr 2026 12:59:57 GMT

Try the Union command. If the triangular solids are clean enough. They should join.