Collide
Here you can select the type of collision calculation for the particles:
- Collide: The classic collision calculation in which particles can interact dynamically with a surface.
- Kill: This deletes the particles when they come into contact with a surface.
- Repel: A force acts on the particles, repelling them from the surface.
Here you can define when a collision should be detected:
- Intersection: A collision will occur when a particle comes into direct contact with a dynamic surface. This is the most accurate method, but with very fast-flying particles it may also be necessary to adjust the intermediate steps so that all collisions are reliably detected. You can find this setting in the Scene Presets under Simulation/Particles.
- Radius: A distance to the surfaces can be defined via a Radius value. If a particle comes closer to a surface than the defined Radius distance allows, a collision will be detected for the particle. This method can often also reliably check faster particles for collisions, but close-ups may show that the particles bounce off slightly before they reach the actual surface.
- Both: Both methods are combined, i.e., both a safety radius in front of the surface and the surface itself will be checked for collisions.
Collision Iterations[1..2147483647]
The accuracy of the particle calculation is particularly important during collision detection, as large distances are covered between the animation images, especially in the case of very fast-moving particles, and collision areas may be overlooked. If you observe this in your simulation, you can improve collision detection by adjusting the collision iterations. The following video gives an example.
There, spherical Base Emitters were placed within spheres to which Collider tags were assigned. The particles are emitted at very high velocities. On the left side just one Iteration was used. Some of the particles manage to penetrate the sphere. A slightly higher iteration value was used on the right-hand side of the video. The particles can be kept inside the sphere.
For the Radius and Both contact settings, the safe distance in front of the surface that is already used for collision detection can be defined here. The greater this distance, the more reliably fast particles can be intercepted in front of a surface.
This value defines the amount of energy that a particle retains after colliding with the surface. Please note that this energy transfer is also controlled by the corresponding setting, e.g., on the object's Collision tag. The fact that this property can be defined on both the Collide object and the bouncing particle means that both elements can be assigned individual values.
This is a drag force that acts on particles at the moment of collision. This means that a colliding particle can also be retained on a surface, for example. The effect can therefore act like an adhesive force between the particle and the surface.
Normally, the angle of a bouncing particle results from the angle at which the particle hits the surface. However, a random variation of this rebound angle can be added via this percentage value.
If you activate this option, the colliding particles can be automatically moved to another particle group that you link in the target group. This makes it easier to assign, for example, a changed appearance or behavior to the colliding particles.
The collision of a particle with a surface can also be used as a Condition. If desired, a Particle Group can also be linked here, into which the particles should be moved by their collision. Activate the Change on contact option to use this link field.
This button can be used to create a new Particle group that is automatically used as a Target group.
By default, all objects that have one of the dynamic Simulation tags (such as a Collision or Rigid Body tag) are evaluated for the particle collision calculation. This is because the list of Simulation tags in the Collision Modifier is empty and the Exclude mode is active. This means that no objects will be excluded for the collision calculation. Alternatively, you can also drag individual dynamic objects into the list of Simulation tags. In Exclude mode, the surfaces of the corresponding objects would then be ignored for the collision calculation.
You can reverse the effect with Include mode. In this case, only the objects that have been linked in the list of Simulation tags will be taken into account for the collision calculation.
By default, all objects that have one of the dynamic Simulation tags (such as a Collision or Rigid Body tag) are evaluated for the particle collision calculation. This is because the list of Simulation tags in the Collision Modifier is empty and the Exclude mode is active. This means that no objects will be excluded for the collision calculation. Alternatively, you can also drag individual dynamic objects into the list of Simulation tags. In Exclude mode, the surfaces of the corresponding objects would then be ignored for the collision calculation.
You can reverse the effect with Include mode. In this case, only the objects that have been linked in the list of Simulation tags will be taken into account for the collision calculation.
Clicking on this button will select all objects in the list for the Simulation tags.