How to Set an Inflow Fluid in Blender

Creating a continuous stream of liquid in Blender requires using the Mantaflow physics engine to configure both a Domain object and an Inflow object. By defining a 3D mesh as an Inflow flow source within an active fluid domain, Blender continuously emits fluid into the scene across your animation timeline. This guide walks you through the step-by-step process of setting up the geometry, adjusting the physics properties, and baking the final continuous fluid simulation.

Step 1: Create the Fluid Domain

Before setting up an inflow, you need a bounding container where the physics calculations take place.

  1. Press Shift + A in the 3D Viewport and select Mesh > Cube.
  2. Scale the cube so it completely encloses the area where your fluid will flow and interact.
  3. With the cube selected, go to the Physics Properties tab (icon looks like a planet orbiting a point).
  4. Click Fluid.
  5. Set the Type to Domain.
  6. Set the Domain Type to Liquid.

Step 2: Create the Inflow Source Object

The inflow object is the mesh geometry from which the fluid continuously spawns (such as a pipe opening, a tap, or a sphere).

  1. Press Shift + A and add a mesh (for example, a Cylinder or UVSphere).
  2. Position and scale the object inside your Domain cube where you want the fluid stream to start.
  3. With the object selected, navigate to the Physics Properties tab and click Fluid.
  4. Set the Type to Flow.

Step 3: Configure the Inflow Properties

To make the fluid emit continuously rather than acting as a single drop or splash, adjust the flow settings:

  1. Set Flow Type to Liquid.
  2. Change Flow Behavior to Inflow.
  3. (Optional) Check Initial Velocity if you want the fluid to shoot out in a specific direction rather than just falling due to gravity. Enter a value along the X, Y, or Z axis depending on the orientation of your emitter.
  4. Ensure the Use Flow checkbox is enabled. You can keyframe this setting on and off if you want the flow to start or stop at specific frames.

Step 4: Enable Mesh Generation and Bake

To view the fluid as actual geometry rather than preview particles, enable the mesh option on the Domain.

  1. Select your Domain cube.
  2. In the Physics Properties tab, scroll down to the Mesh section and check the box to enable it.
  3. Scroll down to the Cache section.
  4. Set the Type to All (or Modular if you prefer baking data and mesh separately).
  5. Set your desired Frame Start and Frame End.
  6. Click Bake All to calculate the continuous simulation.

Once the baking process finishes, press the Spacebar to play the animation and observe the continuous fluid stream emitting from your inflow object.