solution for the stl slicing problem with program names corresponding to the question numbers

one.py

import trimesh
from time import sleep
from savePlot import saveSection

myMesh = trimesh.load_mesh('assignment.stl')
height = int(input('please input height - '))

# hard coded base plane (bottom)

saveSection(2, height, myMesh)
sleep(1)

print('saving sections with height 10mm, 30mm and 50mm')
saveSection(2, 10, myMesh)
sleep(1)
saveSection(2, 30, myMesh)
sleep(1)
saveSection(2, 50, myMesh)
sleep(1)

savePlot.py

from datetime import datetime
import matplotlib.pyplot as plt

def saveSection(basePlane, height, mesh):
    rightNow = datetime.now()

    myMesh = mesh
    if (basePlane == 1):
        height = height + 25
        planeNormal = [0, 0, 1]

    if (basePlane == 2):
        planeNormal = [0, 1, 0]

    if (basePlane == 3):
        planeNormal = [1, 0, 0]

    planeOrigin = [0, 0, 0]
    for i in range(len(planeNormal)):
        planeOrigin[i] = planeNormal[i]*height

    try:
        slicedMesh = myMesh.section(plane_origin=planeOrigin, plane_normal=planeNormal)
        sliced2D, to_3d = slicedMesh.to_planar()
        plt.axes().set_aspect('equal', 'datalim')
        eformat = {'Line0': {'color': 'g', 'linewidth': 1},
           'Line1': {'color': 'y', 'linewidth': 1},
           'Arc0': {'color': 'r', 'linewidth': 1},
           'Arc1': {'color': 'b', 'linewidth': 1},
           'Bezier0': {'color': 'k', 'linewidth': 1},
           'Bezier1': {'color': 'k', 'linewidth': 1},
           'BSpline0': {'color': 'm', 'linewidth': 1},
           'BSpline1': {'color': 'm', 'linewidth': 1}
        }
        for entity in sliced2D.entities:
            if hasattr(entity, 'plot'):
                entity.plot(sliced2D.vertices)
                continue
            discrete = entity.discrete(sliced2D.vertices)
            eKey = entity.__class__.__name__ + str(int(entity.closed))

            fmt = eformat[eKey].copy()
            if hasattr(entity, 'color'):
                fmt['color'] = entity.color
            plt.plot(*discrete.T, **fmt)
            fileName = datetime.now().strftime('section%d%b%Y%H%M%S') + '.png'
        plt.savefig(fileName)
        
        print('section saved with file name ', fileName)

    except AttributeError:
        print('geometry does not exist in the slicing plane')

three.py

import trimesh
from time import sleep
from savePlot import saveSection

myMesh = trimesh.load_mesh('assignment.stl')
height = int(input('please input height - '))
basePlane = int(input('please input base plane -\n1. front\n2. bottom\n3. left'))

# hard coded base plane (bottom)

saveSection(basePlane, height, myMesh)
sleep(1)

print('saving sections with height 10mm, 30mm and 50mm')
saveSection(1, 10, myMesh)
sleep(1)
saveSection(1, 30, myMesh)
sleep(1)
saveSection(1, 50, myMesh)
sleep(1)

two.py

import trimesh
from time import sleep
from savePlot import saveSection

stepHeight = int(input('input the step height - '))
myMesh = trimesh.load_mesh('assignment.stl')

heightSufficient = True
height = 0

while heightSufficient:
    saveSection(2, height, myMesh)
    sleep(2)
    height = height + stepHeight
    if height >= 60:
        heightSufficient = False

print('done!')