You can emit fluid from any polygon or NURBS surface that is inside a fluid container. The fluid emits from the surface towards the closest voxels.

For closed objects, such as spheres, you can emit fluid into the object's volume by turning on the Fill Object in the fluidEmitter node Attribute Editor. See Fill geometry with fluid.
To create a fluid by emitting from an object into a fluid volume
- Create a container.
- Create the polygon or NURBS object you want to emit fluids.
- Move the object or container so that the object is completely inside the fluid container. (An object can emit fluid only when it is inside a fluid container.)
- Select both the object and the container.
- Select
- Modify emitter and fluid attributes as appropriate.
See fluidEmitter and fluidShape.