Lean out

The lean out expression rotates trees towards the nearest include spline boundary, to use it.

1. Create a Forest object with Splines defining the Include areas. Randomise rotation as you would Normally
2. Go to the Effects rollout and enter a value in Lean_Out_Amount. This will determine the angle of the lean effect
3. To adjust the distance from the boundary's edge that the lean out effect influences, edit the Lean_Out_Distance parameter.
4. Because the lean out rotation overwrites any randomised rotation use used in the transform rollout you can reintroduce to rotation variation using the RandomWiggle parameter.

Effect Script​

#Find vector to nearest border
Vector vec1  =  fpItem.areaIncNearest- fpItem.position;
#calculate lean angle
real angle = atan2(vec1.x,vec1.y)-degtorad(90);

#calculate falloff
real leanOutX = easeIN(fpItem.areaIncDistance,Lean_Out_Distance,0,fpItem.rotation.x,sin(angle+degtorad(randomReal(-randomWiggle,randomWiggle)))*Lean_Out_Amount);
real LeanOutY = easeIn(fpItem.areaIncDistance,Lean_Out_Distance,0,fpItem.rotation.y,cos(angle+degtorad(randomReal(-randomWiggle,randomWiggle)))*Lean_Out_Amount);

#assign lean angles to forest item
fpItem.rotation.x = leanOutX;
fpItem.rotation.y = leanOuty;

You can find this Effect within the Forest Effects Library.

This Effect Uses​

Parameters​

• Lean_Out_Amount

  Type: Real

• Lean_Out_Distance

  Type: Scene Units

• RandomWiggle

  Type: Real

Attributes​

• fpItem.areaIncNearest

  Vector to nearest include area edge.

• fpItem.areaIncDistance

  Distance to nearest include area.

• fpItem.position

  Position vector of individual fp Item.

• fpItem.rotation.x

  Individual item's X rotation.

• fpItem.rotation.y

  Individual item's Y rotation.

Functions​

• atan2(x,y)

  Returns the principal value of the arc tangent of y/x, expressed in radians

• degToRad(p)

  Converts degrees to radians.

• easeIn(x,x1,x2,y1,y2) returns an ease-in interpolation between y1 and y2. Returns y1 when x < x1