improve readme example

Author: OrtnerMichael

README.md

@@ -1,6 +1,10 @@
 # Magpylib-Force
 
-This package provides force and torque computation for Magpylib objects. Its work in progress and will finally be integrate into the Magpylib package.
+This package provides force and torque computation for Magpylib objects. It is work in progress and will finally be integrated into the Magpylib package.
+
+This work is supported by a NUMFOCUS grant: SDG 2024 round 1
+
+**Warning:** magpylib-force relies on magpylib version>=5.0.1
 
 # Installation
 
@@ -13,15 +17,40 @@ import numpy as np
 import magpylib as magpy
 from magpylib_force import getFT
 
-source = magpy.magnet.Sphere(diameter=1, polarization=(1,2,3))
+# Note: All inputs and outputs are in SI units.
+
+# SOURCES: Magpylib source objects that generates the field
+s1 = magpy.magnet.Sphere(diameter=1, polarization=(1,2,3))
+s2 = magpy.magnet.Cuboid(dimension=(1,1,1), polarization=(1,2,3))
+
+# TARGETS: targets that experience a force in the field of all sources
+cube = magpy.magnet.Cuboid(
+    dimension=(1,1,1),
+    polarization=(0,0,1),
+    position=(1,2,3),
+)
+cube.meshing = (5,5,5) # regular rectangular mesh in Cuboid
 
-line = magpy.current.Polyline(
+line = magpy.current.Line(
+    vertices=((2,2,2), (3,3,3), (3,2,-3), (2,2,2)),
     current=1,
-    vertices=((0,0,3), (-2,0,-1), (2,0,-1), (0,0,3)),
 )
-line.meshing = 10 # mesh points in each segment
+line.meshing = 15 # number of cells in each segment
+
+# Note: use only closed current loops or be prepared to violate physics
+
+sphere = magpy.magnet.Sphere(
+    diameter=(6/np.pi)**(1/3),
+    polarization=(0,0,1),
+    position=(2,2,2),
+)
+sphere.meshing = 5 # grid finesse - the higher the finer
+
+# COMPUTE FORCE AND TORQUE
+FT = getFT([s1,s2], [cube, line, sphere], anchor=(0,0,0))
+
+# Note: output shape is (3,2,3) from (targets, FT, xyz)
+print(FT)
 
-F,T = getFTcube(cube1, cube2, anchor=(0,0,0))
-print(F)
-print(T)
+# Note: The magnet-numbers are large because the magnets are large :)
 ```