Lidar file format

[jenniferchavez]

Can you create a surface from Lidar .asc format? I can bring it in with the FDO, but i dont know where to go from there to create a surface.

[brian.hailey933139]

You have to either have points in your drawing a point format that can be added to the surface. Not familiar with .asc files but, if you send it to me, I'll take a look. brian dot hailey at cad dash one dot com. I'll be on vacation next week so no guarantees.

[jenniferchavez]

If I cant figure out at least a conversion, Ill be emailing you. Thanks.

[jenniferchavez]

can you create a surface from a point cloud?

[Jmurphy]

Yes No depends...... With just Map3D and SAP you can create a TIF raster surface.

If you can connect to the asc file with data connect then right click on it in the display manger (map task pane) and create a contour file, set the contour inv to 1 foot or so, then save the SDF contour file, turn around and import that sfd file in using mapimport and use the elevation to create OD table. Then either use on of the freebies out there to move the contour lines to their proper elevation (Z property) or the one in C3D or do a map alter property query. That will give you contour lines to build a C3D surface from.

[Glenn Pope]

If your on subscription and using 2010 you can download the Subscription Advantage Pack. That includes extra tool for lidar data. Not sure if its what you need, but worth checking out I think.

http://usa.autodesk.com/adsk/servlet...12&id=13953217

[jenniferchavez]

So I use the point cloud command in subscripton to create a point cloud. Now I have other issues.

1. It is not reading my coordinate system. How does it find that? I have xml files in there. Is there a place I can assign it.

2. How do a make a surface from the point cloud?

[miles9x]

If your .asc file is an ASCII xyz file format you can do it by using the add point file under the regular surface creation tools in prosepctor. You will need to know if it is space or comma delimited, if a point number exists in your points or not, etc.

I have had success with the following work flow: Using the Subscription Advantage Pack, create the point cloud from your data. Then you can create a boundary polyline based on that point cloud in order to leave out any trees, buildings etc. that you wouldn't want in your surface.

Then go to your regular surface creation, create a new surface then under Definition, Point Files, add your ASCII point file along with your polyline boundary previously created from looking at the point cloud.

If you can post your asc or a few lines from the file I can help further.

Miles

[miles9x]

PS. you do not want to import your .asc file as civil 3d points. this will be create undesired results and probably crash your system.