Flow Around Surface

 
 
 

This compound makes particles flow around a surface, avoiding it like an obstacle.

Plug its Execute port into a Port on the ICETree node.

If you want to align the particles to the obstacle's surface, plug the Align Particle to Surface compound's Execute output into an ICETree node's port, then plug the surface object's Value output into the Geometry port of the Align Particle to Surface compound.

For more information, see ICE Particles Flowing Around an Object [ICE Particle Simulations].

Tasks: Particles/Motion Control, Particles/Surface Interaction

Output Ports: Execute

Surface1

The object that the particles flow around. This must be a surface object. Plug its Value output into this port.

Weight

The amount that the particles are repelled from the object.

Proximity Method

The geometry component of the object that is used to calculate the distance for the particle: Closest Surface, Closest Vertex or Knot, or Closest Smoothed Surface.

Enable Cutoff Distance

Toggles the activeness of the Cutoff Distance option.

Cutoff Distance

The maximum distance (in Softimage units) in which the particle considers the object and flows around it.

Falloff Distance Profile

This graph defines the falloff (decay) of the particles movement around the object.

Select Velocity Control Method

The method of controlling the particle speed along the curve:

  • Maintain Velocity

  • Lose Velocity Based on Change in Direction

  • Set New Velocity

New Velocity

If you selected Set New Velocity as the Velocity Control Method, you can set the particle speed here. This is the number of Softimage units the particle moves per second.

Filter Effect Based on Viewing Angle

Toggles the activation of the Viewing Angle Filter Profile.

Viewing Angle Filter Profile

This profile curve lets you make particles ignore the surface object if they are moving away from it, depending on the viewing angle. The curve defines the viewing angle in degrees: at 90 degrees, the particle is moving tangentially to the surface.

You can ramp the effect so that particles do not get caught in orbits when walking around surfaces. They avoid upcoming obstacles, but ignore obstacles that they have already moved past.

Align to Surface Normal

Rotates the particles so that their local Y axes are aligned to the surface normals of the object they are avoiding.

Local Vector

The vector that is used to align the particles. The Y axis is typically the vector that points along the length of a particle. If you change your particle type to cone, you can see that the Y axis is the direction of the cone point. The X and Y axes are the sideways axes.

Alignment Weight

Defines how much the particle is rotated each frame. The value is a ratio, so if you set it to 1.0, the particle is immediately aligned. If you set this value to 0.1, the particle rotates by 10% each frame.