VEX(c)float y = @P.y * chf("y_scale");
float theta = atan2(@P.x, @P.z)* chf("radian_scale");
float value = sin(y + theta);
value = fit(value, -1, 1, 0, 1); // 範囲変換 : (-1, 1) -> (0, 1)
value = pow(value, chf("exponent"));
@Cd = value;
@P += @N * value; // 法線方向に伸ばす