PML - Deformation

By activating this option, parts of the mesh are deformed based on the particles’ speed information. The result is a mesh with a filament-like structure. Depending on the entered value it is possible to create a structure which becomes thicker (or thinner) with growing particle velocity. Deformations can help to visualize speed effects, where very fast parts of the fluid become torn and thin, while slower areas appear slightly thicker. As this effect reduces the amount of detail, the values should be chosen carefully. It might be necessary to change “Blend factor” and “Radius” in combination with these parameters. Deformation looks best with activated filters:

Node Params > Filters > Filter > Yes

Speed stretching

Each particle field (consisting of “Blend factor” and “Radius”) is elongated based on the speed of each particle. This results in some visible stretching and the individual particle might appear like little cylinders. By setting “Speed stretching” to Yes the following input fields are unlocked.

@ Min str scale/@ Max str scale

These values represent the amount of deformation for the “Min speed” and “Max speed” settings entered below. Both range between 0.0 and 2.0.

Speed flattening

Another effect that can be seen in nature with fast travelling fluids is flattening. Drops and parts of the fluids become slightly oval and flattened because of air friction. “Speed flattening” mimics this effect.

@ Min flat scale/@ Max flat scale

Both values determine how strong the flatten effect is pronounced. The settings can range between 0.0 and 2.0.

Min speed/Max speed

The mesh's deformation can also be controlled with the particles' velocity information. You can specify a minimum and maximum value, given in metres per second [m/s], as a threshold: particles with speed values below “Min speed” or above “Max speed” will not be taken into consideration for the deformation effect. In order to evaluate the minimum and maximum speed value, it is a good idea to check the emitter’s "Statistics" window:

Node Params > Statistics > V min / V max