Particle Rendering Mode

Overview

  • Particle (a.k.a. Point, Point Splatting) rendering is the primary rendering mode of Krakatoa.
  • Each particle is considered a point in space without physical extents (radius), carrying information about the density, color, and other properties of the volume it occupies.
  • Each particle can influence one or more pixels in the final image (depending on the selected Filtering settings).
  • In most cases a very large numbers - many millions - of point-sized particles are drawn to produce a smooth result where the individual particles are not distinguishable.
  • In some cases where the rendering is meant to represent naturally particulate matter (e.g. sand), individual particles might.
  • Krakatoa also provides an alternative Voxel rendering mode which can be used as alternative in some cases, for example when flying through dense clouds that may not dissipate into individual points on close-up.

Pros And Cons Of Particle Rendering

  • The main benefits of using particle rendering are:
    • Very fast rendering
    • High sub-pixel detail and very wispy plasma/smoke results can be easily achieved at mid to far distances to the camera.
  • On the negative side, since the particles have no world-space size, moving in too close to the point cloud reveals its point-based nature as the particles do not change their size.
    • Also, they will not blend into a cohesive cloud anymore at short distances, and flying through such a cloud does not produce the expected results.
    • In these cases, the Voxel mode is the preferred approach.
  • Particle rendering typically requires more particles than Voxel rendering to produce solid-looking results, but is usually faster.

Workflow Considerations

  • Rendering in Particle mode generally requires a very large number of particles, typically much higher than it is comfortable to work with directly in the 3D application.
    • For this reason, it is usually a good idea to bake the particles to multiple PRT sequences using the Krakatoa particle saving tools.
    • This will create multiple “Partitions” (also known as Wedges) of the same particle system.
    • They can be combined by a single PRT Loader object which can be transformed, freely retimed and set to display differently in the viewport and at render time.
    • Typically, a fraction of one Partition will be displayed in the viewport, while rendering 100% of all Partitions.
    • This allows for a very fast real-time scrubbing in the scene and rendering dozens and even hundreds of millions of particles on any frame.
  • Note that the render output image size does NOT directly affect the rendering performance of Krakatoa when using Particle mode.
    • Rendering 10 million particles (MP for Million Particles or MegaPoints) at 1K, 2K or 4K resolution will take about the same time to render (although the managing of larger image buffers could have a slight effect).
    • But in order to produce the same high quality rendering at a higher resolution, more particles will be needed, thus indirectly increasing the render times.