Alignment
The modifier offers two modes for using the calculated alignment:
- Alignment: The calculated alignment is transferred directly to the particles.
- Custom: The calculated alignment can be transferred to a user property. This does not result in an alignment of the particles, but you can use the alignment saved in the user property for your own calculations, e.g., within a Particle Node Modifier. User properties can be created via the Scene Preset themselves in order to give the particles their own data packets, which can then be read or written via some conditions and modifiers. In this case, a user property with the data type Quarternions is required.
If you select this mode, you will find a text field directly below in which you can enter the name of your user property that is to save the alignments. However, it can be even quicker to activate the small drop-down menu to the right of this name field. You will find a list of the user properties that have already been created for direct selection.
Use this percentage value to control the effect of the modifier on the particles. At 0% the particles remain unaffected and at 100% the full effect of the modifier is transferred to the particles. Intermediate values lead to a corresponding mixture of the current particle property and modifier property.
The modifier has two different modes:
- Set: The configured change to the particle alignment takes place immediately and without a transition.
- Turn: In this mode, the change in particle orientation can be implemented over a period of time. This allows smoother and more natural-looking alignment changes to be implemented. In addition, a specific Angle can be defined, which is implemented as particle rotation per animation frame or per time span, for example. The following video gives an example. There, the 90-degree rotation of the plane particles takes place over a longer period of time.
When selecting Turn mode, the desired turning angle can be defined here. The speed at which this angle is transferred to the particles is determined by the corresponding mode selection:
- Per Frame: The set angle is transferred to the particles per animation frame. This often results in small Angles being used, which then lead to a uniform rotational speed of the particle systems, for example.
- Per second: The set Angle is applied to the particles over the course of one animation second.
If you are more interested in a continuous rotation of the particle axis systems, the Spin modifier can also be used for this.
Use this menu to select how or to what the Z-axis of the particles should be aligned:
- Axis: Select one of the global world axis directions to align the Z-axes of the particles parallel to it. This will give all particles the same orientation
- Up Direction: The Z-axes of the particles will automatically be aligned in the direction of flight. This gives each particle an individual orientation.
- Random: The axis systems of the particles will be aligned randomly. This calculation is based on the internal key figure of each particle and will only be calculated once and not again in each animation frame.
- Custom: You can define your own vector, which will be interpreted in the global world system and to which the Z-axes of all particles will be aligned in parallel.
- Target: The Z-axes of the particles will be aligned with the position of any object. This will also give each particle a unique orientation.
Here you can select one of the positive or negative axis directions on the world system for Forward Vector Axis. The Z-axes of the particles will then adopt the corresponding axis direction.
If Forward Vector Custom is selected, enter the desired direction for the Z axes of the particles here. This direction vector will be interpreted in global coordinates. The order of magnitude of the vector components is irrelevant. The vector will automatically be normalized.
If Forward Vector Target is selected, any object to whose position the Z axes of the particles should point can be linked here.
This setting is available for all Forward Vector modes except Random and allows you to allow a maximum deviation from the defined alignment by this amount of angle. The proportion of this dispersion can be controlled by the Spread Falloff value.
This can be used to define the frequency and intensity of the alignment deviation. The maximum of the deviations is entered under Spread. The maximum spread will be applied for a Spread Falloff of 0%. At a value of 100%, the defined Spread will be completely suppressed.
The axis system of the particles is three-dimensional and consists of three axes that are perpendicular to each other, as with object axes. The alignment will only affect the Z-axis. If no additional alignment assistance were provided, the particles could rotate freely around the Z-axis, which would make stable alignment of the particles during flight impossible.
For this reason, we use this setting to define a second direction to which the Y-axis of the particles should be oriented. This alignment is secondary and cannot always be maintained perfectly, as the alignment of the Z-axis always has priority. The following can be selected:
- Alignment Up: This algorithm attempts to bring the direction of the Y-axis as parallel as possible to the direction of the global Y-axis, as far as the position of the particle Z-axis allows, as its direction will not be changed by this.
- Custom: You can define your own direction vector to which the Y axes of the particles should be oriented. This vector is interpreted in the global world system. This also does not affect the alignment of the Z-axes on the particles.
For the Custom Up Direction setting, enter the global direction to which the Y axes of the particles should be oriented.
The calculation of all randomness of the Modifier is based on this value. A change in the Seed value also leads to a recalculation of all activated variations, such as the Spread.