Select the PhoenixFDSim1 node and in the Attribute Editor, open the Grid tab. Scroll down to the Grid Adaptation section and note that the Adaptive Grid is set to Temperature / Liquid.
In this setup, the Phoenix FD Simulator will track the Temperature channel and whenever the temperature value of a voxel close to the boundary of the simulator goes past the Threshold parameter value, the size of the grid will increase.
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Keep in mind that the TresholdThresholdvalue depends on the channel being tracked by the Adaptive Grid parameter. Smoke, for example, is in the range [ 0, 1 ] so instead of 1300, the Threshold should be set to 0.01 or lower. You can check the range of any exported channel from the Preview tab of the Simulator.
For a more detailed explanation of the Adaptive Grid parameter, please check the Simulator → Grid documentation.
