wxNviz: confusing to add raster3d isosurfaces

[hamish]

Hi,

I'm testing volumes in wxNviz, using the vox50 example from the wiki:

​http://grasswiki.osgeo.org/wiki/3D#Examples

It's working, but I find the adding-isosurfaces part a bit counter intuitive, and the 3D view was completely blank until I figured out to manually change the viewing height. For the isosurface the main confusion was because it works the opposite way to the [Submit] button when editing vector attributes- there you edit first then hit the "go" button. With the isosurfaces you press the [Add] button first, it creates a new isolevel using the minimum data value, then you change the value from that default by hand and just sort of press enter or change the field somehow and it applies the change silently. (maybe a "go" button to the right of the Isosurface level: text entry box would help even if it did very little besides be yet another way to apply the change? sort of like close-door buttons on elevators which don't do much but are satisfying to press anyway)

Until I figured out I was looking at it all backwards it was all rather confusing.. at first I typed in a value "1000.0" then pressed [Add], and my 1000 was replaced by a 2.5 (the min value) in both the text entry box and the level list. I kept on overwriting the previously entered value adding new "2.5" value levels to the end of the list. Obvious in hind-sight, but it's quite easy to get lost in it when just starting out.

-- Perhaps the fix for this confusion is to simply grey-out the "Isosurface value:" entry box until at least one isosurface has been added with the [Add] button? Then you get the order of buttons to press in your mind from the beginning.

Also just to mention a bit of a bug to look out for: after adding isolevels out of order and moving them up and down in the list, 2 of 4 iso surfaces never rendered. Adding new isosurfaces at nearby (+/-) levels rendered ok. No error messages. It's a little hard to reproduce, I'll post back in a new ticket if I can figure out how to trigger it every time. Perhaps the value is still sitting at 2.5 (default,minimum) instead of the 2000, 3000 showing in the surface level list (??).

Finally, for that data (spatial range is 0..50 in x,y,z) the default viewing height is 5000 if you have no other map layers open, so you see nothing in the display until you realize to manually type in 25 or 50 into the Height: slider control. For cases when 3D view mode starts with 3D rasters alone loaded, could it take a hint from the current region's top/bottom value, or perhaps the first raster3d's values for the same, as to what to set the starting min/max height around? (also, in this case the old Tcl/Tk NVIZ default value of perspective=40 starts it out in a better view than the new wxNviz default of =20)

thanks, Hamish

[hamish]

maybe a "go" button to the right of the Isosurface level: text entry box would help

better: "[modify]"