Force Radial POP

Summary

The Force Radial POP is used in a Particle POP loop and outputs a float3 attribute named PartForce that sums a set of forces defined in the Force Radial POP.

The forces include, first on the Global page, a single global force, plus a Wind Speed converted to a wind force.

These forces are by default uniform for all particles, but because it can be affected by attributes on the Map page, each particle (point) can have a different global force or wind speed applied to it.

Currently the conversion of wind speed to wind force is hard-wired in the Force Radial POP, but more detailed control will be provided in a future build.

On the Force (Local) page, you can choose between Radial, Axial, Spiral and Planar local fore types, with position (Translate), Direction, rolloff (Radius) and Strength controls.

The global and local forces are added together.

In one Force Radial POP, the local force is added to the global and wind forces to generate a PartForce attribute. If the input of the Force Radial POP already exists, then the Force Radial POP's sum of forces is added to the input's PartForce.

Thus you can string a bunch of Force Radial POPs together and optionally mask each one with a Field POP by multiplying its Weight attribute by Force Radial's PartForce attribute.

Assuming PartForce is in the (usually Null) POP at the end of the Particle POP's feedback loop, PartForce feeds back to the Particle POP where it is used to calculate all particles' velocity and position on the next frame of the simulation.

However you can define multiple local forces in one Force Radial POP: To enable many forces to be included in one Force Radial POP, the parameter called Specification POP is a pointer to, usually, a Point POP, where each point of the Point POP defines a separate local force, where the attribute names are matched to the the parameter names (for example, attribute strength represents the Strength parameter). In the Point POP you need to create the appropriate matching attributes.

Then the sum of the local forces are added to the global and wind forces to generate the PartForce attribute.

Note that you can create the PartForce attribute any way you want - using Noise, Math Mix, Pattern, Lookup, GLSL POPs etc. You don't need the Force POP - it is just a convenience.

Parameters - Force Page

Specification POP specpop - Reference to a POP where each point is a specification defining a separate force.

Position pos - ⊞ - Forces center position.

Position posx -

Position posy -

Position posz -

Direction direction - ⊞ - Determines the radial force main direction.

Direction directionx -

Direction directiony -

Direction directionz -

Enable Radial radial - Enable the radial force.

Radial Strength radialstrength - Radial force magnitude.

Enable Axial axial - Enable the axial force.

Axis Rotation axialr - ⊞ - 3D rotation for the axial force direction. The base axis is the Direction.

Axis Rotation axialrx -

Axis Rotation axialry -

Axis Rotation axialrz -

Axial Strength axialstrength - The strength of the force along the Direction axis.

Enable Spiral spiral - Enable the spiral force.

Spiral Rotation spiralr - ⊞ - 3D rotation for the spiral force axis. The base axis is the Direction.

Spiral Rotation spiralrx -

Spiral Rotation spiralry -

Spiral Rotation spiralrz -

Spiral Strength spiralstrength - Spiral force magnitude.

Enable Planar planar - Enable the planar force.

Planar Exponent planarexponent - Planar force distance exponent.

Planar Strength planarstrength - Planar force factor.

Falloff falloff - ⊞ - Sets the falloff type on the forces.

S Curve scurve -

Bias Power power -

Inverse Distance inversedistance -

None none -

Steepness falloffsteepness - Controls the steepness of the S-Curve falloff.

Bias falloffbias - In the S Curve falloff, this biases the curve to fall off closer to its inner limit or its outer limit.

Exponent falloffexponent - Sets the exponent on the distance when enabling falloff by inverse distance.

Radius falloffradius - The radius of the falloff.

Plateau falloffplateau - The plateau of the falloff.

Limit Near-Range fallofflimitrange - The near-range limit of the falloff.

Parameters - Global Page

Global Force globforce - ⊞ - Global force direction.

Global Force globforcex -

Global Force globforcey -

Global Force globforcez -

Global Force Multiplier globforcemult - Multiplier for the global force.

Wind Speed windspeed - ⊞ - Global wind speed.

Wind Speed windspeedx -

Wind Speed windspeedy -

Wind Speed windspeedz -

Wind Speed Multiplier windspeedmult - Multiplier for global wind speed.

Parameters - Map Page

Mapping map - Start of Sequential Parameter Blocks for attribute-to-parameter mapping.

OP map0op - Source OP for parameter mapping. The default of _in0 means the input POP.

Element map0element - The attribute (or component of an attribute) that will be mapped to a parameter per-point.

Parameter map0parm - ⊞ - Parameter on the current POP that will be mapped from the Element (the attribute).

globforce (Global Force) globforce -

globforcex globforcex -

globforcey globforcey -

globforcez globforcez -

globforcemult (Global Force Multiplier) globforcemult -

windspeed (Wind Speed) windspeed -

windspeedx windspeedx -

windspeedy windspeedy -

windspeedz windspeedz -

windspeedmult (Wind Speed Multiplier) windspeedmult -

Combine Operation map0combineop - ⊞ - Combine operation for attribute value with parameter value.

Set set -

Multiply mult -

Add add -

Parameters - Common Page

Bypass bypass - Pass through the first input to the output unchanged.

Free Extra GPU Memory freeextragpumem - Free memory that has accumulated when output memory has grown and shrunk.

Delete Input Attributes delinputattrs - Only output which attributes you specify in this POP - helps isolate attributes into a separate branch.

Operator Inputs

Input 0: -

Info CHOP Channels

Extra Information for the Force POP can be accessed via an Info CHOP.

Common POP Info Channels

Common Operator Info Channels

total_cooks - Number of times the operator has cooked since the process started.

cook_time - Duration of the last cook in milliseconds.

cook_frame - Frame number when this operator was last cooked relative to the component timeline.

cook_abs_frame - Frame number when this operator was last cooked relative to the absolute time.

cook_start_time - Time in milliseconds at which the operator started cooking in the frame it was cooked.

cook_end_time - Time in milliseconds at which the operator finished cooking in the frame it was cooked.

cooked_this_frame - 1 if operator was cooked this frame.

warnings - Number of warnings in this operator if any.

errors - Number of errors in this operator if any.

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