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Point Cloud size question

I ran a point cloud on a 43 acre tract (300 images).

With image scale at full size, the cloud had 162 million points and was split into 6 files. The sixth file only had 2K of data.

With the image scale at 1/2 size, the cloud only had 24 million points and fit in one file.

Is this difference seem correct?  How much difference would the setting of the point density betweein High, Optimal, and Low?  

I am sending the data out to a photogrametry firm to classify the DSM and return a DTM with contours.  This is a test project to see if we can speed up the process and get the engineers a better product.  Pix4d can classify some of the points but there is a lot of clutter and remnants of small bushes and trees.  Our clients want a very accurate surface model to design with.  The photogrametry firm is excited to work with our point cloud and see how this goes with the client performing the data acquisition, adding GCP, and creating the orthomosaic.

Thanks for your help.


Dear William,

We cannot give precise estimates on the number of points generated, since this will depend on many parameters, such as other processing options and crucially the image content. For most projects, we recommend keeping the default settings of half image scale and Optimal point density for the processing options of the second step. 

Please note that we are currently on a new DTM generation algorithm. This is already present in the Preview version of the software, and will be included in the next release, 3.1. We encourage you to give it a try. 

Best regards,