Masking objects allow you to shape your fluid volume by cutting out particles. The entire process is similar to Boolean subtraction operations, but requires a certain workflow.
The blue area should be filled with particles, the white areas should be spared out.
To achieve the look from the image below go through a few steps. In the first step, create four cubes, arrange them, and specify the one you want to fill with particles (named "Fill_Object" here).
- Add a "Fill" emitter and drag the cube, meant to be filled, "Fill_Object" cube to the emitter's "Body" slot.
- Set the emitter's "Fill Mode" to "Fill non Solid Volume".
- Enable the emitter's Mask > From Collision Objects option.
Time to adjust the "Fill_Object" cubeobjects:
- Add "CollisionCollider" and "Volume" tags to the four cubesall four objects – the "Collider" tag tells RealFlow | Cinema 4D that there is an interacting object.
- Select the "Fill_Object" cube's "Volume" tag, and set "Volume Mode" to "Solid Outside".
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