The Parameter suboperator defines exposable values for other suboperators. It is particularly useful when you want to expose the same value for two more different suboperators, such as a random seed, for the purpose of keeping your operator interface simple. For more information, see Equal Data Type.
Interface
- Type
- Choose the data type for the parameter from the list:
- Angle
- Animation Sync
- Float
- Integer
- Percent
- Time
- Uniqueness Seed
- World Unit
With most data types, you can set only the default value; exposing the parameter shows this value in the particle view UI and lets the user change it.
- Value
- Specifies the default value for the parameter.
- Parameters Animation/Uniqueness
- Available with the Animation Sync and Uniqueness Seed data types, respectively. With Animation Sync, choose a Sync By value from the drop-down list; with Uniqueness Seed, set a Seed value.
- Sync By
- If you animate the suboperator parameters, the software can begin applying this animation to all particles as of the start frame of the animation or the first frame of the current event, or to each particle based on its age. The options are:
- Absolute Time Any keys set for parameters are applied at the actual frames for which they're set.
- Event Duration Any keys set for parameters are applied to each particle relative to the frame at which it first enters the event.
- Particle Age Any keys set for parameters are applied at the corresponding frames of each particle's existence.
- Particle Lifespan Scales/maps the animation of the parameters onto the particle lifespan period. For example, if a parameter value is animated from 5-20 over frames 0-100, then this parameter has the value 5 when the particle is born, and the value 20 when the particle dies. This way you can, for example, define the change in a particle's scale over its lifespan.
For this option to work properly, there must be a Delete operator set to By Particle Age in the flow to define particle lifespan.
- Use As Parameter Modifier
- When on, modifies an existing parameter, either by offset, or multiplication factor.
Using the same random seed in several different suboperators can cause correlation issues between different properties. In this case you can create a Parameter suboperator with Type set to Uniqueness Seed, and feed it into one suboperator. For another suboperator, create an additional Parameter suboperator, turn on Use As Parameter Modifier option, and set it to the same data type. Then the parameter connection should go through this additional Parameter suboperator. This way the random seed has an offset, and the random values in the underlying suboperators are not correlated. At the same time you can use a single (original) Parameter suboperator for parameter exposure.
For a usage example, see the included sample file RandomWalk.max. To view the underlying logic of the Random Walk operator, add a Data operator and then use Load Preset to open the Random Walk preset.
- Offset By/Multiply By
- Choose a method and set an amount for modifying the parameter. For the Uniqueness Seed type, only the Offset By option is available. For the Animation Sync data type parameter modification is not possible, so all the new options are unavailable.