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You can restrict the appearance of particles to a domain with “Yes”. The domain's box can be positioned and scaled freely with the parameters under Node Params > Node or the W and R keys.
Emission rate
This is the number of particles which are created per second per cubic metre. The final number of particles also depends on the various threshold values and the used particle type. In some cases it can be necessary to use very high settings of 1,000,000 and more.
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