GetParticleAttribute
This Node can be used to retrieve a single attribute from the particle that the system is currently spawning. As such the node cannot be used with an Emitter block, as the emitter has no particle data and is simply for setting the spawn point and spawning characteristics of the particles. Using this node you can choose to get the current value for the attribute or get the initial value for the attribute. This choice is made by selecting the ParticleLocationType from the Inspector window:
The options here are:
- Current: This will get the current attribute value, which will be updated every frame
- Source: This will get the attribute value at the time the particle was initialised (as set in the Init block) as a static value
Using Source is recommended when you have complex calculations in the initialisation to generate a value and wish to use the same value in the particle update (thus avoiding performing unnecessary complex calculations every frame).
IMPORTANT: It is possible to create an “infinite loop” that will crash the simulation using this node. This happens when you get an attribute, then modify it and try to apply it to itself. For example, if you get the Size attribute, then apply a Multiply to it, then supply the result to the ParticleSize attribute of the Update node, it will generate an infinite loop.
Node Output
This node has the following output:
AttributeType
The attribute type is set from the Inspector window:
The following attribute types are available:
| String | Type | Description |
|---|---|---|
Age | Float | Returns a value that goes from 0 to \[particle lifetime\]. |
AgeOverLifeTime | Float | Returns a value that is between 0 and 1, representing the \[age\] normalised. |
Lifetime | Float | Returns a value representing the total \[particle lifetime\]. |
Position | Vec3 | Returns a vector of the particle position. |
Rotation | Vec3 | Returns a vector of angles (in degrees) of the particle rotation along the x axis, y axis, and z axis.. |
Velocity | Vec3 | Returns a non-normalised vector of the direction for the particle (to be applied after the update pass). |
Size | Float | Returns a value that represents the size (radius) of the particle. |
Scale | Vec3 | Returns a vector that represents the X/Y/Z scale for the particle. |
TextureIndex | Float | Returns the current texture index value for the particle. Note that this value is only relevant when the Output block has the UVMode set to “Atlas”. For more information see the ParticleTextureIndex section of the Update block. |
id | Float | Returns a value that represents the unique ID of the particle. |
Colour | Vec4 | Returns a vector of integer values (from0 to 255 each) corresponding to the RGBA values for the particle. |
VelocityRotationAxis | Vec3 | Returns a vector representing the particle axis in the coordinate space of the effect (world or local depending on the <EmitInLocalSpace> parameter on the emitter block). |
VelocityRotationRate | Float | Returns a float which is the velocity rotation rate in degrees per second. |