Skip to content

Fluid Brush Tool Guide

The Fluid Brush Tool allows you to interactively paint or erase fluid particles directly in the editor viewport. This is useful for:

  • Manually placing particles in specific areas
  • Sculpting initial fluid shapes
  • Removing unwanted particles from the simulation

Step 1: Select the Kawaii Fluid Volume

Click on the Kawaii Fluid Volume in your level to select it. The Details panel will show the "Brush Editor" category.

Brush Details

Step 2: Start Brush Mode

In the Details panel, find the Brush Editor category and click the "Start Brush" button.

Step 3: Configure Brush Settings

Expand the Brush Settings section to customize:

Setting Description Range
Mode Add - Paint new particles / Remove - Erase particles Add, Remove
Radius Size of the brush circle 10 ~ 500
Particles Per Stroke Number of particles spawned per brush stroke 1 ~ 100
Initial Velocity Starting velocity of spawned particles Vector
Randomness Random spread of particle positions 0 ~ 1
Stroke Interval Time between brush strokes while holding click 0.01 ~ 0.5

Step 4: Paint Particles

  • Left-click and drag inside the Volume bounds to paint particles
  • The brush preview circle shows the affected area
  • Arrow indicates the spawn direction (surface normal)

Keyboard Shortcuts

Key Action
[ Decrease brush size
] Increase brush size
1 Switch to Add mode (Green)
2 Switch to Remove mode (Red)
Alt + Left-click Orbit camera (bypass brush)
ESC Exit brush mode

Step 5: Exit Brush Mode

Press ESC or click the "Stop Brush" button in the Details panel.

Tips

  • The HUD displays current mode, radius, and particle count
  • Brush only works within the Volume bounds
  • When painting on static meshes inside the Volume, particles spawn on the surface
  • When painting on Volume walls, particles spawn at the wall with appropriate spawn direction