OPTIMISING THE HAIR IN THE VIEWPORT PREVIEW
in order to preview/playblast animation faster while working on setting correct values for the noise, you can temporarily delete a part of the hair geo. To do that, i created a point node with assigned attribute parameter to the colour with random values, by using the rand(@elemnum) expression. The next step is to create a delete node, with operation set to – delete by expression. in the expression ‘rand(@cd) > .05’: @cd stands for colour, and > .05 means delete everything that has colour value bigger than 0.05.