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Drag Force Daemon

Author: NL Team
Publication: 11/06/2010
Category: Types - Type: Tutorial

Drag Force Daemon

This daemon simulates external air drag forces that slow down faster particles or bodies. A common application would be explosion effects. Without a drag force daemon the explosion would continue expanding forever. Drag force strength normal values range from 0.0 to 1.0 – however this value is often increased for creating more complex effects, such as melting particles. Values greater than 1.0 will slow down the particles/bodies quickly, even if they are exposed to strong external forces.

The shield effect influences the leading particles of the trail slowing down them down, creating the typical shield deformation as shown below. Very high drag strength values can even stop particles or bodies completely. This can cause instabilities in areas where the particles are created. With high values (> 1.0) it’s therefore recommended to use a bounded daemon to increase stability.

Drag strength
This values typically ranges between 0 and 1, but can also accept higher settings. Settings greater than 1.0 may cause instabilities, and force particles and bodies to stop completely.

Shield effect
To activate this option it has to be switched to “Yes”. “No” disables the effect. “Yes” also unlocks the “@ shield inverse” function.

@ shield inverse
Instead of slowing down the leading particles, they are accelerated. Groups of particles can be constricted from the main stream, forming groups.

Force limit
With this parameter it’s possible to restrict the daemon’s maximum strength. This setting accepts any positive or negative value.

Bounded type
You can choose from three options: “None”, “Square” and “Sphere”. “None” does not restrict the forces to a certain area, while “Square” creates a box. “Sphere” applies a spherical domain around the centre. The size of the bounding volume can be adjusted with the daemon’s scale settings under Node. All three values can be changed independently. “Square” and “Sphere” also unlock the daemon’s ability to create an attenuated force field.

It’s often necessary to create a fall-off to enhance realism, because in nature, forces always show some kind of attenuation – depending on the distance to the force’s origin. You can choose from “Linear”, “Square” and “Cubic”. “Cubic” creates the fastest fall-off.

Affect vertex
This function can only be used with rigid bodies and does not influence particles. If set to “Yes” the daemon affects the vertices of rigid bodies, while “No” only affects the centre of mass.

Related Tutorials v5.x
Related Tutorials v4.x