manim-Gearbox

This is a plugin for Manim that enables you to draw realistic looking gears and mechanisms. Mostly based on these tec-science pages: https://www.tec-science.com/mechanical-power-transmission/involute-gear/geometry-of-involute-gears/

Currently supported Involute gear features:

• Basic spur gears
• Inside ring-gears
• Basic rack
• Undercutting (gears with fewer than 17 teeth)
• Profile shifted gears
• Meshing calculation with distance variation

Planned further development:

• Cycloid gears, cycloid rack

Installation

manim-gearbox is a package on pypi, and can be directly installed using pip:

pip install manim-gearbox

Note: manim-gearbox uses, and depends on SciPy and Manim.

Usage

Make sure include these two imports at the top of the .py file

from manim import *
from manim_gearbox import *

Add Gear objects, use mesh_to() method to position 2 gears into meshing. I tend to use 'fill_opacity=1' and 'stroke_opacity=0' options because the stroke increases the gear size by a couple pixels, and gives the feeling of interference.

Examples

2 basic gears

class gear_example(Scene):
	def construct(self):
		# small gear
		gear1=Gear(15, stroke_opacity=0, fill_color=WHITE,fill_opacity=1)
		# larger gear
		gear2=Gear(25,  stroke_opacity=0, fill_color=RED, fill_opacity=1)
		# shifting gear1 away from center
		gear1.shift(-gear1.rp * 1.5 * RIGHT)
		# position gear2 next to gear1 so that they mesh together
		gear2.mesh_to(gear1)

		self.add(gear1, gear2)
		self.play(Rotate(gear1, gear1.pitch_angle, rate_func=linear),
				  Rotate(gear2, - gear2.pitch_angle, rate_func=linear),
				  run_time=4)
		

inner gear

class gear_example_inner(Scene):
    def construct(self):
        # smaller gear
        gear1 = Gear(12, module=1, profile_shift=0.3, stroke_opacity=0, fill_color=WHITE,fill_opacity=1)
        # larger gear with inner teeth
        gear2 = Gear(36, module=1, inner_teeth=True, profile_shift=0.1, stroke_opacity=0, fill_color=RED, fill_opacity=1)
        gear1.shift(gear1.rp * UP)
        gear2.shift(gear2.rp * UP)
        # mesh with 0.15*module larger distance than default
        # bias param is used to define left or right tooth flank shall engage if there is offset and play
        gear2.mesh_to(gear1,offset=0.15,bias=False)

        self.add(gear1)
        self.add(gear2)
        self.play(Rotate(gear1, gear1.pitch_angle, rate_func=linear),
                  Rotate(gear2, gear2.pitch_angle, rate_func=linear),
                  run_time=10)