When we worked up our procedure for importing Lidar into Civil3D a couple months ago, we realized there were way too many steps and way too many hoops to jump through. Hoops preparing the data, through Recap to prepare a RCP/RCS, through Civil3D creating a point cloud, and finally creating the surface. Highly trained professionals have more important things to do with their time than spend it like a well trained circus animal jumping through hoops, so we did something about it.
We decided to release a small subset of our C3DTools, to allow Civil3D users the ability to go straight from Lidar data to a TinSurface. It utilizes the Civil3D API to generate the surface, so it’s Civil3D doing the triangulation, not us. We are reading the points, filtering out only those you want, and pumping them in. Here are the tools we considered needed for the task.
|LIDARCONV||Prompts for a selection of files then converts them to LAZ for maximum compression and compatibility with the tools below. For maximum speed and file integrity, this tool uses RapidLasso’s LasZip for file conversions (with permission).|
|LIDARLIST||Creates a detailed report displayed in your default browser, ready to print. Includes point count, coordinate window, elevation min/max and optionally classifications and subcounts.|
|LIDARMAKE||Create a LAZ file from Tin/Grid surfaces (classification 2 for ground). Includes a surface sampler that writes out points on an virtual grid (user supplies interval) draped onto the surface for reducing existing overly dense surfaces.|
|LIDARPLOT||Plots selected lidar files as point objects in the drawing. Beware that AutoCAD tends to slow down significantly and/or become unresponsive or unstable with massive amounts of points. A separate session is highly recommended.|
|LIDARPROJ||Prompts for a selection of LAS/LAZ files, source and target system names. Then uses AutoCAD’s projection engine to convert the points to the new system (including elevation scaling). New file (with target code appended to name) stored in LAZ format using RapidLasso’s LasZip for maximum file integrity.|
|LIDARTHIN||Creates a reduced point copy of a dense file with various filters. Currently includes Interval (very useful for contours only) and optional elevation min/max removal. Echos percent reduction of each file at command prompt.|
|LIDARTILES||Prompts for a file selection of LAS/LAZ files, then draws rectangles in model space representing the extents of those tiles. Label information includes file name, min/max elevation and total number of points. Optionally include classifications found and the number of points for each.|
|LIDARTIN||Prompts for a file selection of LAS/LAZ files, which classes to use (separate multiples with a comma), then a rectangular window for your area of interest. Any points in a file that fall outside the window are not included. Any files selected that fall outside the AOI are not even scanned for points (saved time).|
This means you can have a massive collection of Lidar files (smaller tile the better) and simply select them all, window off your area of interest and in a short wait, have a TinSurface object ready to work with.
LAZ, The Best Format:
We included support for LAS purely for convenience, but the best file format for your Lidar data present and future is the LAZ file format. It typically consumes about 18% of the space the LAS (or Recap) formats would, and roughly 1.5% of the space an ascii XYZ file would! Other considerations.
- All major lidar products support the LAZ format for read/write.
- The file format is open, documented and free libraries exist for it.
- There are numerous tools available to manipulate these files.
So next time you order Lidar data, tell your provider “LAZ Format” please. Also specify maximum granularity since each small LAZ tile has a bounds header, software can skip an entire file if it’s outside your current area of interest.
- Extract the ZIP contents to a folder (like C:\CADSTUFF).
- Start Civil3D (if not already running).
- Issue the NETLOAD command.
- Browse to the folder from line one above.
- Choose the appropriate DLL for your CAD version.
- Click the [Open] button.
- If you have problems NETLOADing, you may need to unblock the DLLs using Windows Explorer.
- After the first manual load, the add-on will automatically load for subsequent sessions.
- All Civil3D sessions must be closed before DLLs can be deleted or updated.
- You can safely delete any LidarTools20##.dll you are not using.
|20170920||LIDARTILE||Added width, height, thickness in label and zoom extents (to all) after drawing.|
|20171011||LIDARPLOT||Added initial version.|
|20171011||LIDARTHIN||Added initial version.|
|20171011||LIDARMAKE||Added initial version.|
|20171011||LIDARLIST||Added initial version.|
|20171022||Various||Now using extended point count when standard count is zero, to handle LAS 1.4 format change.|