The array property PartImgData provides read-only access to the particle image data. The particle data are organized in NClasses layers, each layer representing one particle class. The parameter ClsIx is the class index (1...NClasses), the returned particle image data contain zero values for all pixels which are not part of any particle, all other pixels (those which belong to particles of the selected class) contain non-zero values reflecting the particle index. The particle index can be used to access the particle parameters via the array ParticleParams.
If ClsIx holds an invalid value the returned array is empty (all zero pixels).