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The Pyro Spawn Sources SOP creates spawn points for sourcing pyro simulations using packed source sets. These points identify the relevant packed sets and store some basic animation data, such as when the source is to engage, how quickly it should play back, and how frequently it should repeat. Additionally, this operator facilitates some basic source rule overrides to adjust rules that come with the packed set.
The spawn points can be modified downstream to adjust (or randomize) their properties, which are stored on point attributes; for example, you can use Attribute Adjust Float to randomize the
startframe values, causing the different sources to engage on different frames. Key point attributes of spawn points are listed below.
Name of the packed source set that we want to instance.
Location of the instance in world space.
Orientation of the instance in world space.
The local pivot point for this instance.
The instance is activated on this playbar frame.
If greater than
startframe, the instance will not be active beyond this
If this value is no smaller than
1, then the source sequence will loop.
The looping sequence starts at
startframe and is
looplength frames in
When the instance first engages (on
startframe), it starts sourcing at
this offset within the packed source set’s frame range.
Length of the subsequence to use from the packed set’s full frame range.
For example, if
5, then only
0-5 will be used for sourcing. If
offsetlength is smaller than
0, then all frames from the packed set can be used.
Playback speed of the source once it engages. For instance, if
2, then offset
1 of the packed set will be
sourced when it first engages, followed by offsets
3, 5, ... on subsequent
frames. This speed can be negative.
Input points to turn into spawn points. If no input is provided, a spawn point will be generated at the origin.y
When specified, only the subset of the input geometry corresponding to this group is modified.
Spawn points will be for the packed source set of this name. This string is
put into the
The source is first engaged on this frame. This value is stored on the
If turned on, the source will not be active after this frame. This value is
stored on the
When the instance first engages, it starts sourcing at this offset within
the packed source set’s frame range. This value is stored on the
When turned on, only offsets of the packed source set in the range between
Start Offset and End Offset will be sourced. This value affects the
Playback speed of the source once it engages. Source Speed can be set
negative, in which case the packed set will animate in reverse. This value
is saved in the
If turned on, a sequence of this length will loop starting at Start Frame. For example, if you start sourcing on frame
6, and Loop Length is
4, then frames
6, 10, 14, ... will all apply the same sources. This value is
saved in the
The spawn points can make adjustments to the packed set’s merging rules using these Rule Overrides. For example, you can turn off a rule by specifying its Target Field and setting the Activation Multiplier to 0.
This parameter is used to identify which rules should be adjusted: any rule that applies to this Target Field will get the override.
Specifies which property of the rule to override. The value of this property for the relevant rule is scaled by Multiplier.
The applied scale factor. The selected Property of any rule that affects the Target Field will be multiplied by the value of this parameter.