Before you can have a collision, you must create the objects that you want to use as obstacles. You can use polygon or NURBS surface objects, but you can’t use implicit objects. As well, the objects can be either stationary or animated. If the obstacle for cloth is animated, it will pull the cloth object with it.
This process describes the basic steps to follow for any simulation collision. However, there are some issues particular to the type of simulation you’re creating:
• For details on setting up collisions for the particle, fluid, or explosion simulators, see Setting Up Particle Collisions.
• For details on setting up hair collisions, see Setting Up Hair Collisions.
• For details on setting up soft-body collisions, see Setting Up Soft Body Collisions.
• For details on setting up cloth collisions, see Setting Up Cloth Collisions.
To select objects as obstacles and set up a collision
1. Select the particle clouds, hair, cloth objects, or soft-body objects (not clusters or tagged points) that you want to have collide with the obstacles.
2. From the Simulate toolbar or Hair panel, choose Modify > Environment > Set Obstacle.
3. Pick one or more objects in the scene that will act as obstacles for the emitted particles, hair, cloth object, or soft body object. Right-click to end the picking session.
4. Set the general and physical parameters in the Obstacle property editor to set up the obstacle and control the collision’s behavior.
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The parameters in the Obstacle property editor (except Friction and Elasticity) are used in calculating obstacle collisions with hair only if the hair’s Collision Type is set to XSI (see Setting Up Hair Collisions). If the Collision Type is set to Actual (default) or Exact, the parameters in this property editor are not considered in the collision. |
5. When you play the simulation, the particles, hair, cloth objects, or soft-body objects collide with the obstacle.
When you set the obstacle object, its name is automatically used and “_obstacle” is appended to it. For example, if the obstacle object is named Wall, the obstacle property is named Wall_obstacle.
To make it easier to tell apart different obstacles, you can rename an obstacle. For example, if you have two different obstacles for an object, one can be called “floor” while another is called “wall”.
To name a force
• Enter a descriptive name in the Name text box in the obstacle object’s Obstacle property editor.
If you modify the name of the obstacle object after this point, the obstacle property is not renamed.
You can temporarily disable the obstacle property, meaning that you can easily test a simulation with or without the obstacle being calculated as part of it. As well, you can animate the muting.
To mute an obstacle
• Select the Mute option in the obstacle’s property editor.
You can easily disconnect obstacles from the simulation objects to which they’re associated. When you disconnect an obstacle from particle clouds, the collision event on the particle type is removed.
To disconnect an obstacle
1. Select the particle, fluid, or explosion cloud, or the hair, cloth, or soft body object to which one or more obstacles is connected.
2. Choose Modify > Environment > Disconnect Obstacle/Force/Emitter from the Simulate toolbar. Pick the obstacles you want to disconnect, then right-click to end the picking session.
SOFTIMAGE|XSI v.6.01