Before starting this tutorial, read:
- Working with Data — Groups, Resource Types, and Prototypes
- Working with MegaWorld Window — how to navigate the window
Step 1 — Open the MegaWorld Window and select Brush Physics
Press Alt + Z to open the MegaWorld Window. In the Tools Panel, click the + button and choose PhysX Painter → Brush Physics.Step 2 — Add a Group and prototypes
In the Selection Panel, click Add Group. Inside the group, click Add Resource and choose Unity/GameObject or Terrain Object. Add the Prefabs you want to spawn.Your Prefabs need Collider components so that the physics simulation can detect collisions with the terrain and other objects. Without colliders, objects will fall through the surface.
Step 3 — Configure the tool settings
In the Settings Panel, set:- Brush Size — the radius of the brush area where objects can land.
- Position Offset Y — the height above the surface at which each object spawns before falling. The default is
30. Increase this for a longer drop; decrease it if objects are landing with too much energy. - Spacing — the minimum brush movement before a new stroke fires.
- Physics Effects — the initial impulse applied to each object at spawn. Leave the force low (or zero) for a simple vertical drop.
Step 4 — Paint in the scene view
Move your cursor into the Scene View. A brush preview shows the area. Click and drag to paint — objects spawn above the brush area and fall onto the surface. They collide with the terrain and each other and freeze once physics settles.Step 5 — Undo if needed
Press Ctrl + Z to undo. A full drag stroke is undone in one step after you release the mouse.What’s next
- Use Precise Physics to drop individual objects at a specific point.
- Use Explode Physics to burst-spawn a group of objects with an outward force.
- Read the full Brush Physics reference documentation.