Confused output options

I have imported Georeferenced images (Phantom 3).  Images are inputting with a Metric wgs84 system.  I have set the output to FEET NAD83 MO East.  I also have GCPs Panels set from on-site GPS (0.1 ft).  Set the GCPs in the project, exported the LAS file to my CAD system that has perimeter shots of piles and some shots on top of the piles (several flat tops).  All the ground shot match elevation within a tenth, but all my topo shots on-top are off by 3’.  As it goes up vertically, it gets worst.

 

Should I set my output to arbitrary or what?  trying to calculate volumes.

Hello John,

The accuracy of the reconstruction depends on the overlap between the images, the visual content of the images and many other parameters. There are differences between the accuracy of different parts of the model based on the GSD of the area, the number of images on which they are visible or how close they are to a GCP. For parts of the model with different elevation the GSD of the images is different. 

Setting the coordinate system for the outputs to arbitrary will probably not change the accuracy issues. For more information about the accuracy of Pix4Dmapper outputs you can take a look here: https://support.pix4d.com/hc/en-us/articles/202558889.

Regards,