MaxwellParticles

Description

This extension enables maxwell to render particles as spheres. These particles can be stored in several file formats, such as .bin, abc, pxy, rpc, typically saved from realflow, or passed as internal data which is stored in the .mxs file.

Besides generating its own geometry, this extension can generate also its own UV coordinates. This is done using one or more of the 39 custom UV generators available. Each particle is assigned a pair of UV coordinates whose value depends on the generator used and the mapped magnitude. To use one of the generators, create a UV channel and assign it the desired custom type, and don't forget to enable loading the appropriate data array.

Example of how to create a MaxwellParticles object, add a uv channel, set its custom type to "Vorticity" and enable loading the particle vorticities array.

CextensionManager* extensionManager = CextensionManager::instance();
CgeometryProceduralExtension* geomProcExtension = extensionManager->createGeometryProceduralExtension( "MaxwellParticles" );
//Get the extension container. When using this method of getting the container,
//nearly all parameters have default values, and there is no need to explicitly set them.
MXparamList* particlesParams = geomProcExtension->getExtensionData();

//Fill the required data
char* filename = "/home/rocco/Emitter01_00023.bin";
particlesParams->setString( "FileName", filename );

//Enable loading particle vorticity data
byte load = 1;
particlesParams->setByte( "Load particle Vorticity", load );

//These two numbers can be obtained parsing the particles file or all the particles sequence
//They're needed to map the values of vorticities from 0.0 to 1.0 to access the texture.
float minV = 0.0;
float maxV = 23.67;
particlesParams->setFloat( "Min Vorticity", minV );
particlesParams->setFloat( "Max Vorticity", maxV );

//Add the procedural object to the scene
Cmaxwell::Cobject obj = scene->createGeometryProceduralObject( "My Particles", particlesParams );

//Let´s add a uv channel...
dword uvIndex; //returned uv channel index. Use this index in the texture map properties to access its uvs
byte isOk = obj.addChannelUVW( uvIndex ); // uvIndex will be set to the actual uv channel number of the object.
//...and set it to a custom UV generator, 17, in this case, vorticity modulus
obj.generateCustomUVW( uvIndex, 17 );

//Now assign a material and set the first BSDF reflectance0º color a texture driven by uv channel 'uvIndex'
//This uv channel, since it is a scalar valued channel, stores its value in the U coordinate.

Parameters

UV Generators

"FileName"

Name of the file that contains particles data. It is a NULL terminated string.

Example:

char* file = "/home/paco/Emitter01_00049.bin"; 
extParam->setString( "FileName", file ); 

"Radius Factor"

Multiplier for the particle radius that is read from the file. Can go from 0.00001 to 1000000 and the default value is 1.

Example:

float rFactor = 0.3f; 
extParam->setFloat( "Radius Factor", rFactor );

"MB Factor"

Multiplier to increase or decrease the amount of motion blur of the particles. Can go from 0.0 to 1000000.0. Default is 1.0.

Example:

float factor = 0.3f; 
extParam->setFloat( "MB Factor", factor );

"Shutter 1/"

Shutterspeed of the active camera. Affects the amount of motion of the particles. It is the inverse of the time the shutter is open.

Example:

float shutter = 125.f;
extParam->setFloat( "Shutter 1/", shutter );

"Load particles %"

Percentage of particles to load. Can go from 0.0 to 100.0, default value is 100.

Example:

float percent = 75.f; 
extParam->setFloat( "Load particles %", percent );

"Create N particles per particle"

This parameter, if set greater than zero, activates the Multipoint feature, creating N more particles around each particle. So, if you have 100 particles and set this parameter to 4, it will create 400 more particles, and the final count will be 500.

Example:

unsigned int nParts = 10;
extParam->setUInt( "Create N particles per particle", nParts );

"Extra particles dispersion"

This parameter sets the size of the cloud of extra particles around each original particle. Can go from 0 to 100000. Default is 0.

Example:

float dispersion = 2.f;
extParam->setFloat( "Extra particles dispersion", dispersion );

"Extra particles deformation"

Sets the amount of deformation of the new particles cloud along the speed vector of the original particle. Can go from 0 to 100000. Default is 0.

Example:

float deformation = 1.1f;
extParam->setFloat( "Extra particles deformation", deformation );

"Load particle Force" "Load particle Vorticity" "Load particle Normal" "Load particle neighbors no." "Load particle UV" "Load particle Age" "Load particle Isolation Time" "Load particle Viscosity" "Load particle Density" "Load particle Pressure"  "Load particle Mass" "Load particle Temperature" "Load particle ID"

These flags enable the extension to load the magnitudes arrays to be used with the corresponding UV generators. Note that loading every array without later using it with the UV generator is a waste of memory and could slow the render process. Use them only if you need them.

The particle ID array is needed only if the Multipoint feature is used.

byte loadArray = 1;
extParam->setByte( "Load particle Viscosity", loadArray );

"Min Force" "Max Force" "Min Vorticity" "Max Vorticity" "Min Nneighbors" "Max Nneighbors" "Min Age" "Max Age" "Min Isolation Time" "Max Isolation Time" "Min Viscosity" "Max Viscosity" "Min Density" "Max Density" "Min Pressure" "Max Pressure" "Min Mass" "Max Mass" "Min Temperature" "Max Temperature"

These values must be set to normalize from 0.0 to 1.0 the values read from the corresponding magnitudes arrays. For vector magnitudes the max and min values should be the max and min modulus of these vectors.

"PARTICLE_POSITIONS"

Particle data can come whether in a file or internally stored in the .mxs file. If a filename is not supplied, the extension checks for internal data, and if successful, loads it. This parameter is a linear array of floats x0 y0 z0 x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 ...., its length is 3*numberOfParticles.

Example:

int numParticles = 4;
float points[ 3*4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
	points[ 3*idx + 0 ] = (float)idx;
	points[ 3*idx + 1 ] = (float)idx;
	points[ 3*idx + 2 ] = (float)idx;
}
extParam->setFloatArray( "PARTICLE_POSITIONS", points, 3*numParticles );

"PARTICLE_SPEEDS"

Linear array of particle speeds, floating point numbers, needed to enable calculation of motion blur: Vx0 Vy0 Vz0 Vx1 Vy1 Vz1 Vx2 Vy2 Vz2...., its length is 3*numberOfParticles.

Example:

int numParticles = 4;
float speeds[ 3*4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
 speeds[ 3*idx + 0 ] = (float)idx;
 speeds[ 3*idx + 1 ] = (float)idx;
 speeds[ 3*idx + 2 ] = (float)idx;
}
extParam->setFloatArray( "PARTICLE_SPEEDS", speeds, 3*numParticles );

"PARTICLE_RADII"

Linear array of particle radii, floating point numbers: r0 r1 r2 r3 r4 r5 r6 .... The length of this array can be either 1 or numParticles. If only one radius is given , it is applied to all the particles, otherwise each particle gets its own radius.

Example:

//Each particle its own radius
int numParticles = 4;
float radius[ 4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
 radius[ idx ] = (float)idx + 0.01f;
}
extParam->setFloatArray( "PARTICLE_RADII", radius, numParticles );

//One radius for all particles
float r = 0.4f;
setFloatArray( "PARTICLE_RADII", &r, 1 );

"PARTICLE_IDS"

Linear array of particle IDs, id0 id1 id2 id3 id4 id5.......needed to enable coherent calculation of multipoint. It is an integer array.

Example:

int numParticles = 3;
int ids[ 3 ];
ids[ 0 ] = 23;
ids[ 1 ] = 9;
ids[ 2 ] = 51;

extParam->setIntArray( "PARTICLE_IDS", ids, numParticles );

"PARTICLE_FORCE"

Linear array of particle force : Fx0 Fy0 Fz0 Fx1 Fy1 Fz1 Fx2 Fy2 Fz2...., its length is 3*numberOfParticles.

Example:

int numParticles = 4;
float force[ 3*4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
 force[ 3*idx + 0 ] = (float)idx;
 force[ 3*idx + 1 ] = (float)idx;
 force[ 3*idx + 2 ] = (float)idx;
}
extParam->setFloatArray( "PARTICLE_FORCE", force, 3*numParticles );

"PARTICLE_VORTICITY"

Linear array of particle vorticity : Wx0 Wy0 Wz0 Wx1 Wy1 Wz1 Wx2 Wy2 Wz2...., its length is 3*numberOfParticles.

Example:

int numParticles = 4;
float force[ 3*4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
 vorticity[ 3*idx + 0 ] = (float)idx;
 vorticity[ 3*idx + 1 ] = (float)idx;
 vorticity[ 3*idx + 2 ] = (float)idx;
}
extParam->setFloatArray( "PARTICLE_VORTICITY", vorticity, 3*numParticles );

"PARTICLE_NORMALS"

Linear array of normals of the field at each particle: Nx0 Ny0 Nz0 Nx1 Ny1 Nz1 Nx2 Ny2 Nz2...., its length is 3*numberOfParticles.

Example:

int numParticles = 4;
float norm[ 3*4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
 norm[ 3*idx + 0 ] = (float)idx;
 norm[ 3*idx + 1 ] = (float)idx;
 norm[ 3*idx + 2 ] = (float)idx;
}
extParam->setFloatArray( "PARTICLE_NORMALS", norm, 3*numParticles );

"PARTICLE_NNEIGHBORS"

Linear array of number of neighbors for each particle: n0 n1 n2 n3 n4 n5...It is an integer array and its length is numberOfParticles.

Example:

int numParticles = 3;
int nn[ 3 ];
nn[ 0 ] = 2;
nn[ 1 ] = 1;
nn[ 2 ] = 1;

extParam->setIntArray( "PARTICLE_NNEIGHBORS", nn, numParticles );

"PARTICLE_UVW"

Linear array of texture coordinates (uvw) at each particle: u0 v0 w0 u1 v1 w1 u2 v2 w2...., its length is 3*numberOfParticles.

Example:

int numParticles = 4;
float uvw[ 3*4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
 uvw[ 3*idx + 0 ] = (float)idx/numParticles;
 uvw[ 3*idx + 1 ] = (float)idx/numParticles;
 uvw[ 3*idx + 2 ] = (float)idx/numParticles;
}
extParam->setFloatArray( "PARTICLE_UVW", uvw, 3*numParticles );

"PARTICLE_AGE"

Linear array of particle age: a0 a1 a2...., its length is numberOfParticles.

Example:

int numParticles = 3;
float age[ 3 ];
age[ 0 ] = 4.3;
age[ 1 ] = 0.1;
age[ 2 ] = 7.2;
extParam->setFloatArray( "PARTICLE_AGE", age, numParticles );

"PARTICLE_ISOL_TIME"

Linear array of particle isolation time: i0 i1 i2...., its length is numberOfParticles.

Example:

int numParticles = 3;
float iso[ 3 ];
iso[ 0 ] = 4.3;
iso[ 1 ] = 0.1;
iso[ 2 ] = 7.2;
extParam->setFloatArray( "PARTICLE_ISOL_TIME", iso, numParticles );

"PARTICLE_VISCOSITY"

Linear array of particle viscosity: v0 v1 v2...., its length is numberOfParticles.

Example:

int numParticles = 3;
float vis[ 3 ];
vis[ 0 ] = 4.3;
vis[ 1 ] = 0.1;
vis[ 2 ] = 7.2;
extParam->setFloatArray( "PARTICLE_VISCOSITY", vis, numParticles );

"PARTICLE_DENSITY"

Linear array of particle density: d0 d1 d2...., its length is numberOfParticles.

Example:

int numParticles = 3;
float den[ 3 ];
den[ 0 ] = 4.3;
den[ 1 ] = 0.1;
den[ 2 ] = 7.2;
extParam->setFloatArray( "PARTICLE_DENSITY", den, numParticles );

"PARTICLE_PRESSURE"

Linear array of particle pressure: p0 p1 p2...., its length is numberOfParticles.

Example:

int numParticles = 3;
float prs[ 3 ];
prs[ 0 ] = 4.3;
prs[ 1 ] = 0.1;
prs[ 2 ] = 7.2;
extParam->setFloatArray( "PARTICLE_PRESSURE", prs, numParticles );

"PARTICLE_MASS"

Linear array of particle mass: m0 m1 m2...., its length is numberOfParticles.

Example:

int numParticles = 3;
float mass[ 3 ];
mass[ 0 ] = 4.3;
mass[ 1 ] = 0.1;
mass[ 2 ] = 7.2;
extParam->setFloatArray( "PARTICLE_MASS", mass, numParticles );

"PARTICLE_TEMPERATURE"

Linear array of particle temperature: t0 t1 t2...., its length is numberOfParticles.

Example:

int numParticles = 3;
float temp[ 3 ];
temp[ 0 ] = 4.3;
temp[ 1 ] = 0.1;
temp[ 2 ] = 7.2;
extParam->setFloatArray( "PARTICLE_TEMPERATURE", temp, numParticles );

"PARTICLE_FLAG_COLORS"

Flag indicating if the particle colors array is present or not. It is an array of length 1. Only usable with internal particles.

Example:

byte flag = 1;
extParam->setByteArray( "PARTICLE_FLAG_COLORS", &flag, 1 );

"PARTICLE_COLORS"

Linear array of color (rgb) at each particle: r0 g0 b0 r1 g1 b1 r2 g2 b2...., its length is 3*numberOfParticles. Only usable with internal particles

Example:

int numParticles = 4;
float rgb[ 3*4 ];
for( int idx = 0; idx < numParticles; idx++ )
{
 rgb[ 3*idx + 0 ] = (float)idx/numParticles;
 rgb[ 3*idx + 1 ] = (float)idx/numParticles;
 rgb[ 3*idx + 2 ] = (float)idx/numParticles;
}
extParam->setFloatArray( "PARTICLE_COLORS", rgb, 3*numParticles );