Point Clouds in AutoCAD Map 3D

My colleague, Jeff Morrow, has written a great article on Point Clouds as they relate to AutoCAD Map 3D and AutoCAD Civil 3D, so be sure to check that out!

In this post, I want to send out a big thank you, and report some of my experiences with the new Point Cloud functionality.

Over the last couple weeks, I have been working to finalize the presentation for my AU class, in addition, I am also preparing for Mike Schlosser’s Analyze This! class where I will be co-presenting.  This will be my 3rd time co-presenting this class with Mike, and it is always a great class, as it exposes users to the analysis capabilities of AutoCAD Map.  The goal of the class is to show the users ‘real-world’ scenarios, with ‘real’ data, and I usually find that people are quite surprised as to the extent of analysis capabilities that Map provides.  This year, Mike sent a survey out to the class attendees to get some ideas and suggestions as to what kinds of analysis people might like to see.  The responses were great, with some very detailed suggestions.

So where am I going with all of this?

Well, for my part of the Analyze This! class I’m going to discuss the point cloud technology and how it can be used to generate a 3D Surface that can be used for analysis, specifically, flood trace analysis.  I’m also going to show Feature Overlay Analysis to overlay parcel data, which includes address information, onto building footprints.

So…  my ideas are formed, and I’m ready to start putting the presentation together. 

One minor problem…  I need some ‘real data’.

Where can I find some LIDAR, and related geospatial data to test these theories?

It just so happens that we’ve had some recent discussions with the City of Saskatoon and I know they have acquired some LIDAR data and they have been looking for options to incorporate this data into their workflows and processes.  So a quick call to one of my contacts at the city and voila, less than 8 hours later I have a 6km x 6km area (36 million points) of bare earth, and full featured LIDAR, as well as the corresponding parcels and building footprints.

I owe a HUGE thanks to Ryan Ottenbreit and Kevin Shewchuk of the Corporate Geographic Information Services (CGIS) Section of the City of Saskatoon, for allowing permission to use this data for demonstration purposes.

The Process…

There are essentially 2 steps to get the LIDAR into a format that can be analyzed in AutoCAD Map 3D:

1. The raw data must be processed to generate the Point Cloud indices via the Point Cloud Manager.  This command allows you to choose your LIDAR data to process in the following formats: standard LAS format (.las ), raw XYZ files (.xyz), and the Pont Cloud file format (.isd).  The result of the Index Generation process is a 3 file set that make up the ‘Point Cloud’: .prmd, .isd, .iati. 
   
   From here, the data can be added to the Map just like a regular FDO Feature Class.  Once the Point Cloud layer is added to the Display Manager, the following Ribbon UI will appear to allow control of stylizing the Point Cloud:
   
   
   
2. The next step is to generate a 3D surface from the Pont Cloud Data.  This surface can then be used for a wide variety of display themes and surface analysis.

A Problem…

I did experience one problem as I was attempting to generate indices on this Point Cloud data…

The data provided from the City of Saskatoon is in the NAD83 CSRS98 coordinate system, so naturally, I tried to specify the proper coordinate system during the index creation process. 

Apparently it did not like this, as the generation failed every time with the following message whenever I tried to specify the CS.

I need to investigate this further, but for now, the moral of the story is…  Don’t try to set the coordinate system during the Point Cloud index creation.

Until next time,
Take care

Warren M.

Comments

[Chase C]

Hey Warren,

Are you talking 3D surface as in raster or TIN? I would guess through FDO it's raster?

If you really appreaciated Ryan you would take him to Vegas :)

[Warren]

Lol, hey Chase,
Yes, this is a 'raster' surface that is generated from the Point Cloud data.

I'd be more than willing to take Ryan to AU... I just think that's going to be a little hard for me to expense! Sorry Ryan... :-)

[Martin Chourre]

Hi Warren,

Nice post. I have a couple comments, if I may. First, I think the Point Cloud is more like a Drawing-based Layer (If you have ever used Display Manager with CAD data) than an FDO Feature Class. It is an AutoCAD object in the drawing dB.
Also, for your CS problem. The index needs to be in EPSG code. The Map CS you are trying to assign does not have a corresponding EPSG code. Try a different CS with similiar parameters/properties. Since you are presenting at AU, I thought you might want the comments.

[Warren]

Thanks for the clarifications Martin!

So the Point Cloud layer just 'seems' like an FDO Feature because it is accessed through the Data Connect button, but in reality it is a 'CAD' object and stored in the DWG db?

I'll look into the EPSG code for the CS problem.
Thanks again!

[Martin Chourre]

Yes, it is kind of like an XREF or Attached drawing. Try deleting the DM point cloud Layer. Can you figure out how to add it back to DM?
The Data button in the toolstrip does have a menu item for displaying the Data Connect dialog, but you cannot access point clouds from the Data Connect dialog. The Data Connect dialog is FDO, but the Data button allows CAD objects to be added to DM as well, right?

[Warren]

True, and it is 'grouped' with the Add Drawing Data at the bottom of the toolstrip, so that's good.

[Stefan Helmer]

Hello,
I've hit a bit of a wall right off the bat here. Curious if anyone else has experienced it. I have a fresh C3D 2010 install with SP2 and the Advantage Pack, and although I do see point cloud features in my Toolspace, in the Task Pane, under Tools, I do not have the Create Point Cloud Index option as is shown in the image above. If anyone has seen this before, let me know!
Thanks!
Stefan