spline force



This node will try to keep particles close to spline and make them move along by applying various forces. Depending on the parameters particles can follow the spline curve more or less strictly.

It accepts particles, positions of voxel grid as input.




Particle Stream - This pin requires a particle stream to be connected. Connection is usually not required if any of the attributes is connected.



Enabled - Enable or disable node evaluation.


#Input (Position) ??? Calculate force at user defined position. Position can be retrieved from particles, voxels or any arbitraty point.


#Input (Grid) ??? Calculate force over the entire voxel grid. This operation is faster than applying force on a voxel-by-voxel basis.




Splines - Select NodeWorks splines you want particles to follow.


Shapes - Select 3ds max splines you want particles to follow. When multiple splines are used the closes spline to the particle will take control. Double click on object name to remove it from the list or use Remove button. You can select multiple objects.


Animated Shapes/Splines - Enable this option if splines are animated in any way. Keeping this option disabled results in faster computations.


Use Mass - If you use mass then heavier particles will be more inert to the motion change.


Samples - In order to achieve faster calculations each spline is pre-sampled with user defined number of samples. Keep this number high if spline has many sharp curves as this will result is smoother and more accurate results.



Grid Properties

This rollout becomes available when voxel grid is connected to the Grid input.


Mode ??? There are two methods how to apply spline force to the voxel grid. In Force mode velocities will be added to the voxel grid. Velocity Blend mode will blend calculated velocities will be mixed with velocities inside the voxel grid.


Blend % ??? Amount of velocity blending. Value of 100% means that grid velocities will be completely replaced with calculated velocities.


Use Smoke ??? Enable this option is you want force to be computed only in voxels with smoke present.


Use Fire ??? Enable this option is you want force to be computed only in voxels with fire present.


Use Temperature ??? Enable this option is you want force to be computed only in voxels with temperature present.


Entire Grid ??? Enabling this option overrides all three previous options. Force will be calculated for all grid voxels regardless of the voxel content.



General Properties

Type ??? Choose the force application based on distance from the spline. The "Constant" option maintains a consistent force regardless of distance. "Falloff" dictates the distance range where force influence gradually diminishes. The "Range??? type defines the specific range within which force is active, excluding any particles or voxels outside this range from its effect.


Range Start - Distance at which the forces strength will fade until the distance reach the Falloff End.


Range End - Distance after which the forces do not exist and particles move freely.


Direction - Force along the spline that forces particles to follow the spline direction.


Direction Var % - Directional force variation.


Attraction - Force towards the spline. This value should be higher on shapes with lots of sharp turns and low on straight ones.


Attraction Var % - Attraction force variation.


Rotation - Force around the spline that forces particle to orbit the shape.


Rotation Var % - Rotational force variation.


Seed - Random number generator seed. Change this value to get different pattern.