POP Sprite dynamics node

A POP node that sets the sprite display for particles.

On this page	Using Sprite Particles Parameters Texture Alpha Bindings Inputs Outputs Locals
Since	13.0

The POP Sprite node adds attributes to specify the sprite display of particles.

This operator modifies the spritepath, spriteuv, spriterot, and spritescale attributes.

Using Sprite Particles ¶

Create a particle system using the Location or Source shelf tools.
Click the Sprite Particles tool on the Particles tab.

Parameters ¶

Activation

Turns this node on and off. The node is only active if this value is greater than 0. This is useful to control the effect of this node with an expression.

Note

This is activation of the node as a whole. You can’t use this parameter to deactivate the node for certain particles.

Group

Only affect a group of points (created with, for example, a Group POP or Collision Detection POP) out of all the points in the current stream.

Texture ¶

Sprite SHOP

The sprite SHOP to display the sprites with. This needs to have the proper procedural shader attached. For convenience, this POP contains a SHOP that can be used.

Sprite Map

The texture map to use. This is linked to the internal SHOP, so it only has effect when the internal SHOP is used. It also cannot be animated per particle. To do so you must either assign a separate Sprite SHOP per particle or use the texture crop on a sprite sheet.

Texture Crop

Controls if the spriteuv attribute will be edited. This attribute handles the cropping of the displayed sprite, allowing you to select different sprites on a sheet.

Mode

You can specify the crop region by an offset/size in 0..1 UV space, or by treating it as a tiled array, which you can create using the Mosaic COP.

Texture Offset

Where, in 0..1 coordinates, to start the sprite.

Texture Size

How big, in 0..1 coordinates, that the sprite should take up in the texture file.

Sprite Index

Which sprite in the sprite sheet to use. This is a linear index that goes over all the sprites in row/column order.

Rows and Columns

How many sprites are in the sheet.

Rotate

Rotates the displayed sprite around the view axis. Measured in degrees.

Sprite Scale

Scales the sprite. Note pscale is also used, this is multiplied by the pscale and allows anistropic shapes.

Alpha ¶

Update Alpha

Should the Alpha attribute be created or updated.

Alpha Type

How to update the alpha.

Constant

Each particle is given the same alpha value.

Ramp

An alpha ramp is given which is evaluated. Each particle has to determine where to evaluate on this ramp by assigning the variable ramp in the VEXpression.

Alpha

The constant value to assign to each particle.

Ramp

Using the computed ramp variable, look up in this ramp to get the alpha value.

Range

The compute ramp value from the VEXpression should be within this range. This range will be mapped to 0..1 and looked up in the ramp.

Thus, to reverse the ramp, you can set this to 1..0

Bindings ¶

Geometry

The name of the simulation data to apply the POP node to. This commonly is Geometry, but POP Networks can be designed to apply to different geometry if desired.

Evaluation Node Path

For nodes with local expressions, this controls where ch() style expressions in VEX are evaluated with respect to. By making this ., you can ensure relative references work. It is important to promote this if you are embedding a node inside an HDA if you are also exporting the local expressions.

Inputs ¶

First Input

This optional input has two purposes.

First, if it is wired to other POP nodes, they will be executed prior to this node executing. The chain of nodes will be processed in a top-down manner.

Second, if the input chain has a stream generator (such as POP Location, POP Source, or POP Stream), this node will only operate on the particles in that stream.

Outputs ¶

First Output

The output of this node should be wired into a solver chain.

Merge nodes can be used to combine multiple solver chains.

The final wiring should go into one of the purple inputs of a full-solver, such as POP Solver or FLIP Solver.

Locals ¶

channelname

This DOP node defines a local variable for each channel and parameter on the Data Options page, with the same name as the channel. So for example, the node may have channels for Position (positionx, positiony, positionz) and a parameter for an object name (objectname).

Then there will also be local variables with the names positionx, positiony, positionz, and objectname. These variables will evaluate to the previous value for that parameter.

This previous value is always stored as part of the data attached to the object being processed. This is essentially a shortcut for a dopfield expression like:

dopfield($DOPNET, $OBJID, dataName, "Options", 0, channelname)

If the data does not already exist, then a value of zero or an empty string will be returned.

DATACT

This value is the simulation time (see variable ST) at which the current data was created. This value may not be the same as the current simulation time if this node is modifying existing data, rather than creating new data.

DATACF

This value is the simulation frame (see variable SF) at which the current data was created. This value may not be the same as the current simulation frame if this node is modifying existing data, rather than creating new data.

RELNAME