Krakatoa Particle Channels

Krakatoa uses particle file formats which support arbitrary channels. The file formats allow for completely arbitrary channel names, but Krakatoa follows some conventions for channel names. This affects the usage of both PRT Files and CSV Files. BIN Files use a predefined mapping between Krakatoa conventions and the channels provided within that file format. Channel names are treated as case sensitive within Krakatoa.

Channel Data Type

An individual particle channel can be any data type from the following types

• float16, float32, float64
• int8, int16, int32, int64
• uint8, uint16, uint32, uint64

Each channel also has an arity, which is how many of the above types it has in a row. Krakatoa uses 3 floats, or a float32[3] channel for Position, and in most cases a float16[3] channel for color types.

Channel Naming Conventions

Krakatoa uses a camel case convention, starting with a capital letter, for channel names. A channel name must start with a letter or '_' character, and must be made up entirely of numbers, letters, and '_' characters. Here are some channel conventions which Krakatoa uses.

Most channels which are indicated as float32 could also be stored in memory or on disk as float16 to save space. This depends on whether the quantization of fitting it into a 16 bit floating point is acceptable. For colors, velocities, and densities, this is usually acceptable, but for position this generally is not.

Position 

float32[3] - Particle Position.

Velocity 

float32[3] - Particle Velocity.

Acceleration 

float32[3] - Particle Acceleration.

Normal 

float32[3] - Particle Normal.

Density 

float32 - Particle Density.

Color 

float32[3] - Particle Color. This is converted to/from 3ds Max map channel 0 (vertex color) where appropriate.

TextureCoord 

float32[3] - Texture Coordinates. This is converted to/from 3ds Max map channel 1 (UVW) where appropriate.

Mapping2, Mapping3, etc. 

float32[3] - Coordinate Mappings. These are converted to/from 3ds Max map channels where appropriate.

Orientation 

float32[4] - Particle Orientation. This is a quaternion representing the orientation of the particle.

Spin 

float32[4] - Particle Spin. This is an angle/axis value, representing the axis and angular velocity of the particle.

MXSFloat 

float32 - Particle Flow MAXScript Float.

MXSVector 

float32[3] - Particle Flow MAXScript Vector.