Are you struggling to turn your Digital Elevation Model (DEM) into a Digital Terrain Model (DTM)? This may sound like a simple task, but varied terrain as well as objects above the terrain (i.e. vegetation, vehicles and buildings) can make it challenging.
I have been successful using Cyclone 3DR from Leica. This software has many tools and uses outside of the terrain modeling workflow, but I’ve found it to be very useful when implementing this workflow.
Where’s Your Point Cloud?
Whether your point cloud was made with photogrammetry from a drone or from LiDAR, Cyclone 3DR handles large files with ease. Unlike other software with DTM tools, the coordinate system you’re using and if it matches doesn’t matter to Cyclone 3DR. Just make sure your import and export units are correct and you’ll be set!
Cut, Clean, Rinse and Repeat!
Over-collecting data is a best practice, so it is very common. However, when you’re creating a deliverable, cut and clean out what you don’t need to easily define your working area. If you’re worried about cutting too much, use the Split Tool instead of deleting the data.
Slide the T Into the DM – The Terrain Into the Digital Model
Now that you’ve cleaned the perimeter of your point cloud, run either the DTM Tool or Split Ground Tool to get points that represent the ground. If you’re having issues, the classification of points is based mostly on slope analysis. So, use the previous clean/cut tool to create “sections” of like slope, then run the tool again.
When the terrain points are where you want them, generate your mesh and contours, then you’re all set! These contours are great at creating a comparative volume analysis (existing to design) in Autodesk Civil 3D.
This blog is written by Sr. Reality Capture Technical Specialist David McQuillan. If you have any questions or need help with your Reality Capture needs, please email us at whyATG@atgusa.com.