Community
Civil 3D Forum
Welcome to Autodesk’s Civil 3D Forums. Share your knowledge, ask questions, and explore popular AutoCAD Civil 3D topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Best Way to Import a Surface

3 REPLIES 3
Reply
Message 1 of 4
sarah_karan
803 Views, 3 Replies

Best Way to Import a Surface

In the projects I am currently working on I am going to spatial data download and downloading the DEM files for my area. I then go to toolspace and insert my DEMs through the DEM files folder. I have found though that it slows my drawing down tremendously and even causes it to crash at times. It honestly makes the drawing almost unusable at times- I use the boundary feature and data clip it to as small as possible but even then it causes so many issues. I looked into downloading the contour data as a shapefile from nationalmap.gov but have found that the information is not near as accurate. Just wanted to see what others are doing and what the best way to import surfaces is? 

Labels (3)
3 REPLIES 3
Message 2 of 4
cwr-pae
in reply to: sarah_karan

I typically use a 3rd party program to trim dems down. Global Mapper is the one we purchased, but i understand there are free ones available. I also create an empty surface and then add the dem data as opposed to creating one from a dem. Though I'm not sure that has much effect on speed.

Message 3 of 4
sarah_karan
in reply to: cwr-pae

Thanks for the advice about trimming outside of C3D, that could help. I believe that is also how I insert the DEMs as I right-click on Surfaces and click create Surface.

Message 4 of 4
Pointdump
in reply to: sarah_karan

Hi Sarah,
DEM's are a derivitive product, once removed from the original LiDAR data.
LAS or LAZ files can either be run through ReCap or you can use DotSoft's excellent free >>>Lidar Tools<<<.
As you import a ReCap RCS file into Civil 3D, there is a step which allows you to decimate the points to any spacing, e.g., 1mm, 1 meter, etc. That way you can adjust the surface size to make sure it's under 2 million points, and you won't create the dreaded MMS file which is a death sentence for a surface.
Dave

Dave Stoll
Las Vegas, Nevada

EESignature

64GB DDR4 2400MHz ECC SoDIMM / 1TB SSD
NVIDIA Quadro P5000 16GB
Windows 10 Pro 64 / Civil 3D 2024

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Rail Community


 

Autodesk Design & Make Report