One common question is how to stop the emission of new particles? There are several methods to do this.
HyFLIP
Defining a Volume
The relevant settings are located in the Hybrido emitter node under HY_Emitter node > Node Params > Emitter:
- When “Stream” is set to “No” RealFlow creates a certain number of particles based on the shape of the object under Node Params > Emitter > Object.
- Once the simulation starts no more particles will be created. This mode is comparable to the “Volume” option of the → Dyverso and → standard particle emitters.
Stream Animation
In simulations where “Stream” is set to “Yes” it is possible to animate the parameter:
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- Let's say the emission of particles should stop at frame 50.
- Stream > Yes
- Shift the timeline slider to frame 49.
- Click on the dot next to the “Stream” parameter.
- Go to frame 50, set “Stream” to “No”, and click again on the dot.
- Right-click on “Stream” and choose “Open curve”. The “Curve Editor” is opened.
- Select the two keys and click on “Set Selected Points Type to Stepped” (see image below).
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Stream Expression
A very simple, yet effective method is to manage emission with an → expression:
- Right-click on “Stream” and choose “Open curve”. The “Curve Editor” is opened.
- In the empty field to the left of "Delete Expression" enter:
if(f>49,0,1) - This expression says that if the current frame is greater than 49 the “Stream” option will be set from “Yes” to “No”.
- These two states are represented as binary numbers here – : 1 and 0.
Dyverso Emitters
Defining a Volume
Some Dyverso emitters let you define a certain volume that is filled with particles:
- Emitter node > Node Params > emitter-specific section (e.g. “Circle”) > Volume
- “Sphere” and “Fill Object” have a built-in fill option.
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The next two methods are exactly the same as described under “HyFLIP” and use animation keys and an → expression. The only difference is that with SPH standard particle emitters the “Speed” parameter is animated and set to 0:
- Emitter node > Node Params > emitter-specific section (e.g. “Circle”) > Speed
If you work with an expression, you need two arguments: 0.0 and the emitter's current speed. By default, this is 2.0:
- Right-click on “Stream” and choose “Open curve”. The “Curve Editor” is opened.
- In the empty field to the left of "Delete Expression" enter:
if(f>49,0.0,2.0) - This expression says that if the current frame is greater than 49 the “Speed” parameter will be set from 2.0 to 0.0.
Standard Particle Fluids
Particle Limit
Another idea is to define a particle limit with
- Emitter node > Node Params > Particles > Max Particles
- Just enter a number, e.g. 75000, and the emitter will stop to create new particles once this limit has been reached (in most cases you get a few more particles).
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