– Free is a fraction of particle lifetime expressed as a percentage value, from 0 to 0.99

– In this examples particle’s lifetime is 400 frames.

– Free =0: the particles follow the curve guide in 400 frames.

– Free=0.5: the particles run the whole curve guide in 200 frames (as 50% of 400 is 200), then they are free.

– And….what about Hairs? As you know Curve Guide Force can also be used to control the shape of hairs. In this example you can see how the Free parameter affects the shape of a single hair for a better comprehension.
– In this example you can focus on two points:

-1 The closer to the emitter point the curve guide the more the shape reflects the shape of the curve guide. I find it’s not so easily predictable the shape of the hair when the Curve is far from its root.
-2 Free=0.5 means only one half of the hair is affected by the Curve, in this example I rendered a single big hair made by 32 segments so only the first 16 segments are affected by the Curve Guide Force.

Force Curve Guide Free