GearBox

Original author: GarryBGoode

Source repository: GitHub

License: MIT (see the upstream repository for the full license text)

GearBox is a Manim plugin for drawing realistic involute gears and mechanisms. The geometry is based on the tec-science involute gear article.

The code is bundled inside manim_extensions as the manim_extensions.gearbox subpackage and is also kept as a Git submodule under third_party/.

Features

• Basic spur gears (Gear)

• Inside ring-gears (inner_teeth=True)

• Basic rack (Rack)

• Undercutting for gears with fewer than 17 teeth

• Profile-shifted gears

• Meshing calculation with distance variation via mesh_to()

Quick start

Because the module is included in manim_extensions, you can import it directly (from manim_extensions.gearbox import *). A common rendering style is stroke_opacity=0 and fill_opacity=1, because the stroke slightly enlarges the gear and can look like interference.

Two meshing gears

Example: GearExample

from manim import *
from manim_extensions.gearbox import Gear

class GearExample(Scene):
    def construct(self):
        gear1 = Gear(15, stroke_opacity=0, fill_color=WHITE, fill_opacity=1)
        gear2 = Gear(25, stroke_opacity=0, fill_color=RED, fill_opacity=1)
        gear1.shift(-gear1.rp * 1.5 * RIGHT)
        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,
        )

from manim import *
from manim_extensions.gearbox import Gear

class GearExample(Scene):
    def construct(self):
        gear1 = Gear(15, stroke_opacity=0, fill_color=WHITE, fill_opacity=1)
        gear2 = Gear(25, stroke_opacity=0, fill_color=RED, fill_opacity=1)
        gear1.shift(-gear1.rp * 1.5 * RIGHT)
        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 ring gear

Example: InnerGearExample

from manim import *
from manim_extensions.gearbox import Gear

class InnerGearExample(Scene):
    def construct(self):
        gear1 = Gear(
            12, module=1, profile_shift=0.3,
            stroke_opacity=0, fill_color=WHITE, fill_opacity=1,
        )
        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)
        gear2.mesh_to(gear1, offset=0.15, bias=False)

        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,
        )

from manim import *
from manim_extensions.gearbox import Gear

class InnerGearExample(Scene):
    def construct(self):
        gear1 = Gear(
            12, module=1, profile_shift=0.3,
            stroke_opacity=0, fill_color=WHITE, fill_opacity=1,
        )
        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)
        gear2.mesh_to(gear1, offset=0.15, bias=False)

        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,
        )

See the original README for animated examples and further details.