Hello.
Most of price aggregated data types use time session parameter to specify period of candles from which PA bars will be constructed.

Strategy can customize this parameter in corresponding implementation of ITailoredFeedDescriptor interface when subscribing to data feed.
See example for Kagi Strategy.java
Range bars can be customized using DataInterpolationDescriptor parameter, Tick bars are always built from ticks.
Time aggregation candles in HT now are built from ticks, but interpolation also can be applied to speed up testing process.
Kind regards, Support Team.