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Obsolete Krakatoa File Operators in Particle Flow

  Available in: Krakatoa v1.1.0 and higher up to v1.5.0.
  Deprecated in Krakatoa v1.5.1 and higher - will load from old files but does not appear in the UI.

Overview

  • Krakatoa v1.0.0 provided the experimental Krakatoa File Birth and Krakatoa File Position operators which only worked with a constant particle count between frames.
  • Krakatoa v1.1.0 replaced them with the more advanced Krakatoa File Birth, Krakatoa File Update and Krakatoa File ID Test operators which could be used with varying particle count, but could only load or nothing, without support for Viewport %.
  • These Operators were available in the Particle Flow Depot until Krakatoa v1.5.0 for backwards compatibility and were replaced with the more advanced Krakatoa PRT Loader Birth and Krakatoa PRT Loader Update operators which use a PRT Loader object's particle stream as the source and have a lot less limitations.
  • The Krakatoa File Birth and Krakatoa File Update have been deprecated in v1.5.1 and higher:
    • They will not appear in the Particle Flow Depot, but are still creatable and will load correctly from older files.
    • This is to encourage the use of the new PRT Loader based operators and reduce Depot clutter.

File Birth Operator

  • The File Birth Operator can be used to give birth to particles according to a particle file sequence.
  • Other than the legacy Krakatoa File Birth operator which could load only a static frame, this operator allows the dynamic creation and, in combination with the File ID Test operator discussed below, removal of particles to match the behavior of the actual file sequence. For this feature to be usable, the sequence must contain a valid Born ID channel. The operator will compare two consecutive files from the sequence and determine which particles from the current frame's file do not exist in the previous file. These particles have to be added to the flow.
  • The Operator provides the following controls:
    • Particle File - click the [...] button to open a file picker and select a valid PRT, CSV or BIN particle file or file sequence. If the selected file does not contain an ID channel, a prompt will appear and the particle order will be used instead, potentially leading to incorrect results.
    • Frame Offset - this integer value can be used to offset the particle sequence in time.
    • Single Frame Only - when checked, only the exact file name specified in the Particle File field will be loaded regardless of the current time. When unchecked (default), the frame number of the file (if available) will be replaced with the current time signature and the attempt will be made to load the file as a frame of a particle file sequence.
    • Limit To Custom Range - when checked, the two Range spinners will be used to clamp the file sequence in a user-defined interval. Any attempt to load a lower or higher frame number than the specified Range will result in the frame with number corresponding to the range limit to be loaded instead. This is to prevent from loading non-existent frames.
    • Link To Object TM - when checked, the Transformation Matrix of the PFlow Emitter object will be used to transform the particle positions and velocities. When unchecked (default), positions and velocities will be loaded in absolute world coordinates.

File Update Operator

  • The File Update Operator can be used to apply particle data from a particle file sequence to existing PFlow particles, typically created by the File Birth operator.
  • It also compares the particle IDs from the previous and the current frame and marks those that have to die in a dedicated FileID channel. The values from this channel can be tested using the Krakatoa File ID Test.

Features

  • The operator can be set up to read any of the available channels in the particle sequence and
    • Write them to their default corresponding channels in PFlow (i.e. Position->Position, Color->Color etc.)
    • Redirect the data to other channels with the same data type (i.e. Color->TextureCoords; Normals->Mapping#10 etc.)
    • Combine the incoming with the existing data using Blend or Add modes
    • Blend amounts can be keyframed over time (for example blend 60% of file's Velocities with 40% of particle velocities; add 30% of file's velocities to the existing velocities etc.)
  • The Operator provides the following controls:
    • Particle File - click the [...] button to open a file picker and select a valid PRT, CSV or BIN particle file or file sequence. If the selected file does not contain an ID channel, a prompt will appear and the particle order will be used instead, potentially leading to incorrect results.
    • Channel Setup - this button opens the modeless Channel Setup dialog.
    • Frame Offset - this integer value can be used to offset the particle sequence in time.
    • Single Frame Only - when checked, only the exact file name specified in the Particle File field will be loaded regardless of the current time. When unchecked (default), the frame number of the file (if available) will be replaced with the current time signature and the attempt will be made to load the file as a frame of a particle file sequence.
    • Limit To Custom Range - when checked, the two Range spinners will be used to clamp the file sequence in a user-defined interval. Any attempt to load a lower or higher frame number than the specified Range will result in the frame with number corresponding to the range limit to be loaded instead. This is to prevent from loading non-existent frames.
    • Link To Object TM - when checked, the Transformation Matrix of the PFlow Emitter object will be used to transform the particle positions and velocities. When unchecked (default), positions and velocities will be loaded in absolute world coordinates.

Channel Setup

  • The Channel Setup button opens a new floating dialog showing all Particle Channels found in the currently selected file sequence.
    • The Checkbutton represents the name, type and loading state of a Particle Channel. When checked, the channel will be loaded. When unchecked, it will be ignored.
    • The Color Swatch symbolizes the Arity (number of components) in the Channel.
      • Red= One Component, i.e. Float or Integer value
      • Green = Two Components (2D vector)
      • Blue = Three Components (3D vector like Position, Velocity, Color, Normal etc.)
      • Yellow = Four Components (Quaternion like Orientation)
    • The Target Channel drop-down list shows possible Particle Flow channels the File Data could be copied to. This list is currently hard-coded but could be expanded.
    • The Blend Mode drop-down list shows the available data blending modes (Blend and Add). Default is Blend.
    • The Blend Amount spinner shows the amount of data to be blended with the existing values in the Channel.
      • The default value is 100.0, which in Blend mode means "Replace existing data with File Data".
      • The Blend Amount value is keyframable over time, allowing for gradual blending of data over time.
      • Since blending the Particle ID makes no sense, the spinner will be disabled for the ID channel.
    • The Keys [>>] button provides additional features related to keyframing the Blend Amount spinner.
      • Currently, the only available feature is Delete All Keys which removes the Blend Amount animation from the Channel.