[BUG] - How to get the bottom profile data

tudelft3d / City3D

Large-scale LoD2 Building Reconstruction from Airborne LiDAR Point Clouds

https://github.com/tudelft3d/City3D

GNU General Public License v3.0

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[BUG] - How to get the bottom profile data #43

Closed WS517 closed 2 months ago

WS517 commented 2 months ago

Dear Professor, I want to input the large-scale scene point cloud for modeling, but I only have point cloud data, no bottom contour data, I tried to utilize CLI_Example_1, but failed, how should I get the bottom contour data?

LiangliangNan commented 2 months ago

Please read the ReadMe file carefully because it tells when to use what. Again:

CLI_Example_1 is suitable for data with footprint. You can use whatever method or data sources to obtain the footprint.
CLI_Example_2 is suitable for data without footprint. Besides, the input must be point clouds of individual buildings. You can use whatever method accessible to you to segment the point cloud into individual buildings.

WS517 commented 2 months ago

Thanks for your answer, but I was wondering if it is possible to use CLI_Example_1 or CLI_Example_2 or City3D-GUI to get the footprint data of the input large field attraction cloud? Looking forward to your reply, thank you very much!

LiangliangNan commented 2 months ago

City3D focuses on the reconstruction (i.e., converting 3D points to mesh models), rather than the segmentation. However, it does provide functionalities that could extract footprint for individual buildings (but not for entire scenes).

WS517 commented 2 months ago

Thanks for your answer,but I would like to know how did you get the footprint data of your large-scale raw input point clouds.Looking forward to your reply, thank you very much!

LiangliangNan commented 2 months ago

What I know that might have footprint data:

The cadaster of city/country. Many countries have the footprint data, most of which are managed by the cadaster. The cadaster may have already made such data public, or you can contact them for more details.
Some open data platforms, e.g., OpenStreetMap, offer footprint data. What I know is https://tudelft3d.github.io/3dfier/building_footprints_from_openstreetmap.html
Many published papers address instance segmentation of urban buildings from point clouds. You can try any of these methods and see if it meets the requirement.