"Linear" is a two-dimensional emitter in the shape of a straight line. You can position (W key) and rotate (E) this emitter, but for scale changes we recommend the emitter's “Length” parameter.
Height
This creates a rectangle filled with particles. Simultaneously, “Speed” is set to 0.0. “Height” is measured in metres.
Length
You should change the emitter’s length with this parameter, instead of using the → “Scale” settings under "Node". "Scale" is available, but works like a multiplier, if “Length” is activated: an emitter with “Length” = 3.0 and “Scale X” = 2.0 has a total length of 6 units. The value is given in metres.
Speed
Here the particles' initial speed is defined in metres per second. Higher values will generate more particles per frame. Faster particles act with stronger forces on other particles or objects. The number of emitted particles also depends on your → “Resolution” settings. A value of 0.0 → stops the emission of particles.
V random
To avoid regular emission, it is possible to randomly displace the particles with these functions. The value should range between 0 and 1, but can be higher, as well. “V” stands for vertical.
H random
To avoid regular emission, it is possible to randomly displace the particles with these functions. The value should range between 0 and 1, but can be higher, as well. “H” stands for horizontal.