I see that there are already two other posts on this issue, but unless I missed something, I didn't find a solution/workaround for this warning.
** Warning ** Indicated Zone Volume <= 0.0 for Zone=THERMAL ZONE 1
** ~~~ ** The calculated Zone Volume was=-3.18
** ~~~ ** The simulation will continue with the Zone Volume set to 10.0 m3.
** ~~~ ** ...use Output:Diagnostics,DisplayExtraWarnings; to show more details on individual zones.
It seems that the reason that the zone volume is calculated as a negative number, is due to the direction in which one of the volume's surfaces was drawn. How do I ensure that the vertices are drawn counterclockwise in Sketchup?