@dave r said:
UTC setting isn't a scene-specific setting. It's a model setting like geo-location, dimension units, credits, etc.
When you save a scene you can specify for the Shadow Settings to be saved with the scene.
The UTC Value is part of the Shadow Settings dialog box.
The UTC drop-down is part of the time and date settings because its value can change during different seasons. Although time zone is a geographical region and stays the same for the location of your model, the UTC value needs adjusting with the date.
Technically UTC does not change with a change of seasons, but local time may change if a time zone jurisdiction observes daylight saving time (summer time).
Since SU does not take Daylight Saving Time into account when generating shadows, changing the UTC is the only way to factor DST into your simulation.
For example, SU sets the default Geo-location for the model to Boulder Colorado and the UTC to UTC-7:00. This UTC value is only good during winter. In summer you have to change the UTC value to UTC-6:00.
All this is important for SU users who need to produce accurate shadows.