I'm working on my first UAS topo project for an engineer that I'm pretty sure uses Civil3D. I'm fairly certain on how I am going to proceed with the project. However, I'm not quite sure how to handle the deliverable of the DTM to the engineer. I'm using [REDACTED] to generate the surface and while it can produce a TIN based on my point cloud which can be output to LandXML to go into Civil3D, a TIN file with hundreds of millions of points would be massive and probably hard to handle on the engineer's end. Ideally, it appears that point cloud data is better put into a raster grid DEM format sampled at a desired grid spacing. Can Civil3d take that kind of non-vector elevation data for an engineer to use? Anybody have experience with this kind of thing? Thanks
I haven't used [REDACTED] but generally we find that generating a square grid provides what is required, pick a suitable size grid for the terrain and the job (and your clients computer!). Typically we have output grids with 10, 5, or 2 metre spacing - points as simple XYZ spots.
You might need to set different grid sizes in different areas of the site, depending on the terrain. If necessary you might also need to trace out the main strings (tracks, breaks of slope, etc). We can get this by visual tracing - in out case we use Trimble RealWorks (free viewer) to move through the point cloud and our survey software can read the pointer coordinate display from RealWorks and create a DTM string point each time the mouse is clicked.
It takes some time, but it beats trekking round the country on foot.
Bow Tie, contact Spledus, he uses [REDACTED] and can probably point you in the right direction.
Chris explained it best. Really no other way. If you're mapping flat or rolling terrain you extract grid points and adjust the size of your point spacing to create a manageable TIN. If you're mapping roads with crown, curbs, walls, and steep terrain then you will need to extract the breaklines from the point cloud, and combine this with your reduced grid.
I convert [REDACTED] to Carlson where I merge the ground survey data.?ÿ I then export to LandXML and use LandXMLin to create a Civil3d Surface Object.
Just beware and look at the Civil3d settings before importing the LandXML.?ÿ If you have a bunch of points (like most LiDAR surfaces) and you elect to import the points, Civil3d gets bogged down (at least 2014 does, AutoDesk has not made my list of programs to keep up with).