automated dataset scaling incorrectly computed

[clyne]

When loading the UGRID data set in /glade/p/cisl/vast/vapor/Bugs/2886 the viewing transformation is incorrectly calculated and nothing is visible. The partial workaround is to manually change the scale factor from the default to 1.0 under Scene/Viewpoint. However, further adjusting the Z scaling factor does not achieve desired results (scaling about the center of the Z domain). It looks like the origin is not being calculated correctly. The Z range for this data are ~6378000. to ~6395000, but the origin is set to 0.0

N.B. The grid information is stored separately from the data; both grid.nc and dtotal.00000.nc must be loaded.

[sgpearse]

Probably related:

https://vapor.discourse.group/t/3d-scaling-volume-rendering-issue-along-the-z-axis/149