Hi @gustavhf
Thank you for writing to us. To answer your question:
What exactly is the LiDAR data used for in the processing?
If you use a LiDAR enabled iOS device, and choose to upload your project with the “Process with depth” enabled, the LiDAR data is used directly in two ways:
- To estimate a more accurate scale* of the reconstruction and
- To fill low texture areas that photogrammetry alone is not able to reconstruct.
It is important to note that visible features are still needed in all the images, even if the LiDAR data is used.
in which areas can I expect a LiDAR processed model to differ from one without LiDAR enabled?
To give you an example, please check out these two projects: project processed without LiDAR and project processed with LiDAR. Notice the holes in the point cloud of the project processed without the LiDAR and see how these holes are filled out in the project processed with the LiDAR. Particularly in areas that photogrammetry is unable to create “tie points”, it takes the help of the LiDAR data to fill those areas.
The “Process with depth” option is still in beta, meaning that we already see it working well for many cases, but is still being evaluated and improved before we can guarantee the same level of quality as the other Pix4D processing options.
*Accurate scale depends on a lot of factors, but most important is that the content of the images is of good quality, (good lightning and visible feature details) and covers the scene well.