# PointDeviation maximum distance / minimum distance report needed - solved

Request - Add Maximum distance and Minimum distance to the statistics reported.

PointDeviation in V6 does not report the maximum and minimum distances anywhere. It only reports mean distance, median distance and standard deviation.Maximum distance and Minimum distance should be added to the statistics reported in the pop-up panel.
Example file for PointDeviation: PtDevTest01.3dm (80.1 KB)

PointDeviation in V5 adds in the command line dialog Maximum distance and Minimum distance to the statistics reported in the pop-up panel. Example:
Point test statistics:
Total points: 99
Close point count: 90
Average distance: 0.279798
Median distance: 0.235763
Standard deviation: 0.18479
Maximum distance: 0.80271
Minimum distance: 0

Can this tool be used to get min/max/median distance between two surfaces?

My initial test says no, so is there a different tool I can use for that?

In the screenshot above, I’m not sure if I entered “correct” settings for the very confusing tool (it doesn’t have any auto range, like the curvature analysis has, for example), and the minimum distance is not correct according to a script I received from these forums (that was within 0.01mm of Autodesk Alias’s surface distance measurement tool).

Yes, but …

If a surface is used as the object then a set of sample points is extracted from the surface. The algorithm used in selecting the number and locationof sample points is not obvious, but for planar or surfaces with a simple structure only a few points may be used, which can cause misleading results. More sample points provide better accuracy.

If I need more sample points from a surface than are automatically generated I usually use the contour command to create a set of curves on the surface, and then either use those curves as the source of points (WIP/V7 only) or Divide the curves.

It would be useful if there was an option to specify a minimum number of points to be extracted from a surface.

Huh, you’re correct… it’s 3 points when the surface is flat, and this many when I add curvature to it:

The script I’m using by @Helvetosaur creates its own points by internally generating a surface mesh and getting the vertices from that, which I think could work for this too, especially with the maximum edge length in the mesher.

@Pascal or @John_Brock who can you ping for this? This feature was recently updated for V7 so there has to be an active developer in charge that can fix this.