Particle Flow PRT Data Reloading

Overview

Krakatoa allows you to save the particles from the scene to particle files which cache the state of various data channels per frame in a history-independent fashion. This means that any frame from the sequence can be reloaded and rendered by Krakatoa directly without knowledge of the previous frames.

Obviously, this does not allow you to make changes to the overall particle animation and events, but lets you snapshot the state of the system and perform certain modifications to the particle data channels within the single frame using the Krakatoa Channel Modifiers.

In addition, several Particle Flow Operators have been provided to allow the reloading of the particle data back into Particle Flow as an additional caching path. These operators have been updated with each major release of Krakatoa:

Krakatoa v1.0.0

  • The Krakatoa Birth and Krakatoa Update operators were considered a bonus feature and had a huge amount of limitations.
  • In particular, they did not support changing particle count, only constant count throughout the animation.
  • They were thus only useful in the case where all particles were born on one frame and never died.
  • These operators were removed from later builds.

Krakatoa v1.1.0

  • The Krakatoa File Birth and Krakatoa File Update operators were introduced. They had the ability to use an ID channel (containing the Born ID of the particles) and could determine what particles were born and what particles died from one frame to another. Using a Krakatoa File ID Test operator, the dead particles could be sent to a Delete event.
  • In addition, any saved channels could be selected for loading with Blend or Add mode options and the ability to copy the data into other channels.
  • Main limitation of these operators was the fact the viewport count would always be 100% of the saved particles regardless of the Particle Flow View % settings.

Krakatoa v1.5.0 and higher

  • The Krakatoa PRT Loader Birth and Krakatoa PRT Loader Update were introduced, with the File Birth and File Update still available for backwards compatibility.
  • The major changes in the new operators are:
  • Particles are taken from a selected PRT Loader’s stream, thus all loading and channel processing is performed by the PRT Loader, including timing adjustments, particle deformations and culling, Krakatoa Channels Modifiers on the stack and so on.
  • The ability to load channels in Blend or Add mode is still provided, but the copying of channels to other channels has been removed since it is now possible to do the same and much more using KCMs.
  • The new operators respect the % in Viewport settings of Particle Flow (while also respecting the Render % of the PRT Loader).
  • The existing Krakatoa File ID Test operator can be used with the new operators to remove the dead particles.

Detailed Documentation

  • See here for a description of the Krakatoa PRT Loader Birth and Update operators.
  • See here for a discussion of the Krakatoa PRT Loader Birth and Update operators usage
  • See here for a description of the outdated Krakatoa File Birth and Update operators.