is it possible to create tin surface from DEM/SRTM file in bricscad?

aridzv
aridzv
edited May 2021 in 3D Modeling

Hi.
Is it possible to create a tin surface from DEM/SRTM in bricscad?
at the moment, I use QGIS to create contours from SRTM, then export those contours to DXF, save it as DWG file and crate a tin surface from those contours.
I'm looking for a way to eliminate the need for QGIS...
Thanks,
Ari.

Comments

  • Terry Dotson
    Terry Dotson
    edited May 2021

    A DEM file is a GridSurface, not a TinSurface, so I seriously doubt you will ever see BricsCAD creating a TIN from it. Also beware that true DEM files are integer based so the elevations are rounded to the nearest meter. Not exactly quality!

    Depending on your location, you may find some high quality government supplied Lidar, then you can use this free add-on to import that.

    https://www.bricsys.com/applications/a/?lidartools-a1420-al2455

  • aridzv
    aridzv
    edited May 2021

    @Terry Dotson
    Hi and thanks for the reply.
    I'm doing irrigation and water supply works - not municipal engineering, and that's set my accuracy determination.
    First,
    I'll try this free add-on you mentioned, Thanks!
    second:
    at the moment I use DEM from either https://earthexplorer.usgs.gov/ or from SRTM Downloader plugin in QGIS.
    in your opinion - are those sources accurate?
    thanks,
    Ari.

  • Terry Dotson
    Terry Dotson

    You will need to determine the accuracy (time limited here). All I know is the .DEM file format is integer based, that being the elevation values rounded to the nearest meter.

  • aridzv
    aridzv

    @Terry Dotson
    I've downloaded the Add-on.
    the add-on required .LAS files and I get .GeoTiff files from usgs or qgis.
    any advice on how to convert .Tiff files to .LAS files?
    I've tried to google it but no good results...

  • Terry Dotson
    Terry Dotson
    edited May 2021

    .TIF (Grid) Files are NOT Lidar (Point) Files. Look back, I never said the tool would help with your Grid Files. I said if you can obtain quality Lidar it would help.

    However, since you have .TIF files instead of .DEM you shouldn't have to worry about rounding to the nearest meter.

  • aridzv
    aridzv

    @Terry Dotson said:
    .TIF (Grid) Files are NOT Lidar (Point) Files. Look back, I never said the tool would help with your Grid Files. I said if you can obtain quality Lidar it would help.

    However, since you have .TIF files instead of .DEM you shouldn't have to worry about rounding to the nearest meter.

    @Terry Dotson
    Thanks.
    the add-on is good and when and if I will get .LAS files I'm Shure it will be good!
    and about .tiff files - I will continue with QGIS... :)
    and again - thanks for your help!
    regards,
    Ari.