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Collisions

Particles, Soft Bodies and Cloth objects may collide with mesh objects. Boids try to avoid Collision objects.

  • The objects need to share at least one common layer to have effect.
  • You may limit the effect on particles to a group of objects (in the Field Weights panel).
  • Deflection for softbody objects is difficult, they often penetrate the colliding objects.
  • Hair particles ignore deflecting objects (but you can animate them as softbodies which take deflection into account).

If you change the deflection settings for an object you have to recalculate the particle, softbody or cloth system (Free Cache), this is not done automatically. You can clear the cache for all selected objects with CtrlB → Free cache selected.

See details about rigid bodies collisions here.

Mode: Object Mode

Panel: Physics context → Collision panel

Options

Collision panel in the Physics context.
Permeability
Fraction of particles passing through the mesh. Can be animated with Object F-curves, Perm channel.
Stickiness
How much particles stick to the object.
Kill Particles
Deletes Particles upon impact.
Damping Factor
Damping during a collision (independent of the velocity of the particles).
Random damping
Random variation of damping.
Friction Factor
Friction during movements along the surface.
Random friction
Random variation of friction.
A softbody vertex colliding with a plane.

Soft Body and Cloth Interaction

Outer
Size of the outer collision zone.
Inner
Size of the inner collision zone (padding distance). Only effective for softbodies, cloth only use outer collision value.

Outside and inside is defined by the face normal, depicted as blue arrow in (A softbody vertex colliding with a plane).

Damping Factor
Damping during a collision.

Softbody collisions are difficult to get perfect. If one of the objects move too fast, the soft body will penetrate the mesh. See also the section about Soft Bodies.

Force Field Interaction

Absorption
A deflector can also deflect effectors. You can specify some collision/deflector objects which deflect a specific portion of the effector force using the Absorption value. 100% absorption results in no force getting through the collision/deflector object at all. If you have 3 collision object behind each other with e.g. 10%, 43% and 3%, the absorption ends up at around 50% (100×(1-0.1)×(1-0.43)×(1-0.03)).


Examples

Image 2: Deflected Particles.

Here is a Meta object, dupliverted to a particle system emitting downwards, and deflected by a mesh cube:

Hints

  • Make sure that the normals of the mesh surface are facing towards the particles/points for correct deflection.
  • Hair particles react directly to force fields, so if you use a force field with a short range you don’t need necessarily collision.
  • Hair particles avoid their emitting mesh if you edit them in Particle mode. So you can at least model the hair with collision.




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For the current 2.7x manual see http://www.blender.org/manual/


User Manual

World and Ambient Effects

World

Introduction
World Background

Ambient Effects

Mist
Stars (2.69)


Game Engine

Introduction

Introduction to the Game Engine
Game Logic Screen Layout

Logic

Logic Properties and States
The Logic Editor

Sensors

Introduction to Sensors
Sensor Editing
Common Options
-Actuator Sensor
-Always Sensor
-Collision Sensor
-Delay Sensor
-Joystick Sensor
-Keyboard Sensor
-Message Sensor
-Mouse Sensor
-Near Sensor
-Property Sensor
-Radar Sensor
-Random Sensor
-Ray Sensor
-Touch Sensor

Controllers

Introduction
Controller Editing
-AND Controller
-OR Controller
-NAND Controller
-NOR Controller
-XOR Controller
-XNOR Controller
-Expression Controller
-Python Controller

Actuators

Introduction
Actuator Editing
Common Options
-2D Filters Actuator
-Action Actuator
-Camera Actuator
-Constraint Actuator
-Edit Object Actuator
-Game Actuator
-Message Actuator
-Motion Actuator
-Parent Actuator
-Property Actuator
-Random Actuator
-Scene Actuator
-Sound Actuator
-State Actuator
-Steering Actuator
-Visibility Actuator

Game Properties

Introduction
Property Editing

Game States

Introduction

Camera

Introduction
Camera Editing
Stereo Camera
Dome Camera

World

Introduction

Physics

Introduction
Material Physics
No Collision Object
Static Object
Dynamic Object
Rigid Body Object
Soft Body Object
Vehicle Controller
Sensor Object
Occluder Object

Path Finding

Navigation Mesh Modifier

Game Performance

Introduction
System
Display
Framerate and Profile
Level of Detail

Python API

Introduction
Bullet physics
VideoTexture

Deploying

Standalone Player
Licensing of Blender Game

Android Support

Android Game development