Only modify layers if their names match this pattern. The default pattern allows any layer to be modified. You can speed up the node by only listing layers that are actually modified by the snippet.

For example, in the following snippet, only the density layer is modified. The temperature layer is not modified, only read.

@density = @temperature;

However, for obscure reasons, the node will both modify density and copy temperature. This uses time and memory. To prevent this, you could set this parameter to density to prevent the node from copying temperature. Of course, this requires that you explicitly manage the list of writable layers.

Requires that you declare @ bindings in snippets as prototypes before using them. This applies to both attributes (for example @Cd) and “convenience” bindings such as @ptnum and @Frame. For example:

// Declare bindings
int @ptnum;
float @Frame;
vector @Cd;

// Use bindings after declaration
int pointnum = @ptnum;
float red = @Cd[0] / @Frame;

Automatic binding with the @ syntax can be convenient, but as your scene becomes more complex there is the risk that a typo in an @ binding will silently just bind a non-existent attribute.

VEX functions like ch() usually evaluate with respect to this node. Providing a path here can override where the path search starts from. This is useful for embedding in a digital asset where you would like the top level digital asset to be the search root.

This pattern can be used to override the export option on the VEX shader to avoid writing to certain volumes. The pattern matches the VEX parameter, not the bound volume. The volume will still be bound for reading.