main/src/georegression/transform/se/InterpolateLinearSe2_F64.java
public static void interpolate(Se2_F64 a , Se2_F64 b , double where, Se2_F64 output) {

		double w0 = 1.0-where;

		output.T.x = a.T.x*w0 + b.T.x*where;
		output.T.y = a.T.y*w0 + b.T.y*where;

		// interpolating rotation is more difficult
		// This only works well if the difference between the two angles is small
		double yaw0 = a.getYaw();
		double yaw1 = b.getYaw();

		double cw = UtilAngle.distanceCW(yaw0, yaw1);
		double ccw = UtilAngle.distanceCCW(yaw0,yaw1);

		double yaw;
		if( cw > ccw ) {
			yaw = yaw0+ccw*where;
		} else {
			yaw = yaw0-cw*where;
		}
		output.setYaw(yaw);
	}
public static void interpolate(Se2_F64 a , Se2_F64 b , double where, Se2_F64 output) {

		double w0 = 1.0-where;

		output.T.x = a.T.x*w0 + b.T.x*where;
		output.T.y = a.T.y*w0 + b.T.y*where;

		// interpolating rotation is more difficult
		// This only works well if the difference between the two angles is small
		double yaw0 = a.getYaw();
		double yaw1 = b.getYaw();

		double cw = UtilAngle.distanceCW(yaw0, yaw1);
		double ccw = UtilAngle.distanceCCW(yaw0,yaw1);

		double yaw;
		if( cw > ccw ) {
			yaw = yaw0+ccw*where;
		} else {
			yaw = yaw0-cw*where;
		}
		output.setYaw(yaw);
	}
Perform linear interpolation

@param a The first transform
@param b The second transform
@param where from 0 to 1, inclusive.  0 means it will be more similar to 'a'.
@param output The interpolated transform