Counting and curving

The beginning of the video is for CoyHot and the second part for Nicholas8681, but I guess you other guys can watch too :)

Some more info in the commit message.

Refreshed force fields

Yay! After a long silence I have something new for you guys again!

Unified effector functionality for particles, cloth and softbody

• Unified scene wide gravity (currently in scene buttons) instead of each simulation having it's own gravity.
• Weight parameters for all effectors and an effector group setting.
• Every effector can use noise.
• Most effectors have "shapes" point, plane, surface, every point.
  • "Point" is most like the old effectors and uses the effector location as the effector point.
  • "Plane" uses the closest point on effectors local xy-plane as the effector point.
  • "Surface" uses the closest point on an effector object's surface as the effector point.
  • "Every Point" uses every point in a mesh effector object as an effector point.
  • The falloff is calculated from this point, so for example with "surface" shape and "use only negative z axis" it's possible to apply force only "inside" the effector object.
• Spherical effector is now renamed as "force" as it's no longer just spherical.
• New effector parameter "flow", which makes the effector act as surrounding air velocity, so the resulting force is proportional to the velocity difference of the point and "air velocity". For example a wind field with flow=1.0 results in proper non-accelerating wind.
• New effector fields "turbulence", which creates nice random flow paths, and "drag", which slows the points down.
• Much improved vortex field.
• Effectors can now effect particle rotation as well as location.
• Use full, or only positive/negative z-axis to apply force (note. the z-axis is the surface normal in the case of effector shape "surface")
• New "force field" submenu in add menu, which adds an empty with the chosen effector (curve object for corve guides).
• Other dynamics should be quite easy to add to the effector system too if wanted.
• "Unified" doesn't mean that force fields give the exact same results for particles, softbody & cloth, since their final effect depends on many external factors, like for example the surface area of the effected faces.

Known issues

• Curve guides don't yet have all ui buttons in place, but they should work none the less.
• Hair dynamics don't yet respect force fields.

I know it's quite a lot of new functionality, but it should mostly work just like old force fields, just better and more predictably :). In the future I'll also try to make some tutorial videos about the more interesting ways of using the new force field options.