Radius for Local Modeling

[JonnaCello]

I'm relatively new to CloudCompare and have a question regarding the cloud-to-cloud distance tool. Based on what I've read, I should use 'Local modeling' instead of 'General parameters' for my point clouds. I also believe I should use the Quadratic function and the Radius (instead of kNN). However, I cannot for the life of me figure out how to determine what my Radius value should be. I know the default value is just an estimate that CloudCompare is making, and that I should change the value. However, I have no idea how to figure out the best radius for my point clouds. Is there a tool I can use to determine my radius?

[daniel]

Ah that's tricky.

Ideally the radius should be based on the scale of what your object (i.e.: at what scale the surface is smooth / regular enough to be modeled by a simple quadric or plane), but it will also depend on your cloud density (as you need a minimum number of points to construct a local model - I believe it's 3 for the plane, and 6 for the quadric).