Mobjects - ManimVTK

What are Mobjects?

Mobjects (Manim Objects) are the visual elements in your scenes - everything you see in a ManimVTK animation is a mobject:

Geometric shapes (circles, squares, polygons)
3D objects (spheres, cubes, surfaces)
Text and mathematical equations
Graphs, plots, and coordinate systems
Custom drawn paths

Mobjects are the building blocks of ManimVTK - understanding them is key to creating great animations

Mobject Hierarchy

Mobject (base class)
├── VMobject (vectorized 2D shapes)
│   ├── Circle, Square, Triangle
│   ├── Line, Arrow, Vector
│   ├── Text, Tex, MathTex
│   └── Polygon, Rectangle
├── ThreeDMobject (3D objects)
│   ├── Sphere, Cube, Cone
│   ├── Surface, ParametricSurface
│   └── Prism, Cylinder, Torus
└── VGroup (container for grouping)

Creating Mobjects

Basic 2D Shapes

from manimvtk import *

class BasicShapes(Scene):
    def construct(self):
        # Circle
        circle = Circle(radius=1, color=BLUE)
        
        # Square
        square = Square(side_length=2, color=RED)
        
        # Triangle
        triangle = Triangle(color=GREEN)
        
        # Rectangle
        rectangle = Rectangle(width=3, height=1.5, color=YELLOW)
        
        # Arrange and display
        shapes = VGroup(circle, square, triangle, rectangle)
        shapes.arrange(RIGHT, buff=0.5)
        
        self.play(Create(shapes))
        self.wait()

Basic 3D Objects

from manimvtk import *

class Basic3DObjects(ThreeDScene):
    def construct(self):
        # Sphere
        sphere = Sphere(radius=1, color=BLUE)
        
        # Cube
        cube = Cube(side_length=1.5, color=RED)
        
        # Cone
        cone = Cone(base_radius=0.5, height=1, color=GREEN)
        
        # Arrange
        objects = VGroup(sphere, cube, cone)
        objects.arrange(RIGHT, buff=1.5)
        
        self.set_camera_orientation(phi=60 * DEGREES, theta=30 * DEGREES)
        self.play(Create(objects))
        self.wait()

Text and Math

from manimvtk import *

class TextAndMath(Scene):
    def construct(self):
        # Regular text
        text = Text("Hello, ManimVTK!", font_size=48)
        
        # Mathematical equation
        equation = MathTex(r"E = mc^2")
        
        # Arrange vertically
        VGroup(text, equation).arrange(DOWN, buff=1)
        
        self.play(Write(text))
        self.play(Write(equation))
        self.wait()

Mobject Properties

Color

# Set color at creation
circle = Circle(color=BLUE)

# Set color after creation
circle.set_color(RED)

# Gradient color
square = Square()
square.set_color_by_gradient(BLUE, RED)

# RGB values
circle.set_color(rgb_to_color([0.5, 0.7, 0.9]))

Opacity

# Stroke opacity (outline)
circle.set_stroke(opacity=0.8)

# Fill opacity (interior)
circle.set_fill(opacity=0.5)

# Overall opacity
circle.set_opacity(0.7)

Size

# Scale
circle.scale(2)  # 2x larger
circle.scale(0.5)  # Half size

# Set specific dimensions
rectangle.width = 3
rectangle.height = 2

# Stretch in one direction
square.stretch(2, 0)  # Stretch horizontally

Position

# Shift (relative movement)
circle.shift(RIGHT * 2)
circle.shift(UP + LEFT)

# Move to absolute position
circle.move_to(ORIGIN)
circle.move_to([1, 2, 0])

# Align
circle.to_edge(LEFT)
circle.to_corner(UR)  # Upper right

Rotation

# Rotate around center
square.rotate(PI / 4)  # 45 degrees

# Rotate around a point
square.rotate(PI / 4, about_point=ORIGIN)

# Rotate around axis (3D)
cube.rotate(PI / 2, axis=UP)

Styling Mobjects

Stroke (Outline)

circle = Circle()

# Stroke color
circle.set_stroke(color=BLUE)

# Stroke width
circle.set_stroke(width=5)

# Combine
circle.set_stroke(color=BLUE, width=3, opacity=0.8)

Fill (Interior)

square = Square()

# Fill color
square.set_fill(color=RED)

# Fill opacity
square.set_fill(opacity=0.5)

# Combine
square.set_fill(color=RED, opacity=0.7)

Combining Stroke and Fill

# Circle with blue fill and red outline
circle = Circle()
circle.set_fill(BLUE, opacity=0.5)
circle.set_stroke(RED, width=3)

Grouping Mobjects

VGroup

Group multiple mobjects together:

# Create individual shapes
c1 = Circle()
c2 = Square()
c3 = Triangle()

# Group them
group = VGroup(c1, c2, c3)

# Operations on group affect all members
group.arrange(RIGHT, buff=1)
group.set_color(BLUE)
group.scale(0.5)

Arrangement

shapes = VGroup(*[Circle() for _ in range(6)])

# Arrange in a row
shapes.arrange(RIGHT, buff=0.5)

# Arrange in a column
shapes.arrange(DOWN, buff=0.5)

# Arrange in a grid
shapes.arrange_in_grid(rows=2, cols=3, buff=0.5)

# Arrange in a circle
shapes.arrange_in_circle()

Copying Mobjects

# Simple copy
circle1 = Circle()
circle2 = circle1.copy()

# Copy and modify
circle2.shift(RIGHT * 2)
circle2.set_color(RED)

# Deep copy (for complex objects)
import copy
complex_group = VGroup(...)
copy_of_group = copy.deepcopy(complex_group)

Mobject Methods

Common Methods

get_center()

Get the center point:

center = circle.get_center()
print(center)  # [x, y, z]

get_width() / get_height()

Get dimensions:

width = rectangle.get_width()
height = rectangle.get_height()

get_color()

Get current color:

color = circle.get_color()

rotate()

Rotate the mobject:

square.rotate(PI / 4)

scale()

Scale the mobject:

circle.scale(2)  # Double size

shift()

Move relative to current position:

circle.shift(RIGHT * 2 + UP)

Alignment Methods

# Align to edges
mobject.to_edge(UP)
mobject.to_edge(LEFT)

# Align to corners
mobject.to_corner(UL)  # Upper left
mobject.to_corner(DR)  # Down right

# Align relative to other mobject
circle.next_to(square, RIGHT)
circle.next_to(square, DOWN, buff=0.5)

# Move to specific position
mobject.move_to(ORIGIN)
mobject.move_to([1, 2, 0])

Custom Mobjects

Creating Custom Shapes

from manimvtk import *

class CustomStar(VMobject):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        # Define your custom shape
        points = [...]  # Define points
        self.set_points_as_corners(points)

Using Paths

# Custom path
path = VMobject()
path.set_points_as_corners([
    ORIGIN,
    UP,
    UP + RIGHT,
    RIGHT
])
path.set_stroke(BLUE, width=3)

Surfaces and Parametric Objects

Parametric Surface

from manimvtk import *
import numpy as np

class ParametricSurfaceExample(ThreeDScene):
    def construct(self):
        surface = Surface(
            lambda u, v: np.array([
                u,
                v,
                np.sin(u) * np.cos(v)
            ]),
            u_range=[-2, 2],
            v_range=[-2, 2],
            resolution=(30, 30)
        )
        
        surface.set_color_by_gradient(BLUE, GREEN, RED)
        
        self.set_camera_orientation(phi=60 * DEGREES)
        self.play(Create(surface))
        self.wait()

Common Parametric Surfaces

# Torus
torus = Surface(
    lambda u, v: np.array([
        (2 + np.cos(v)) * np.cos(u),
        (2 + np.cos(v)) * np.sin(u),
        np.sin(v)
    ]),
    u_range=[0, TAU],
    v_range=[0, TAU]
)

# Sphere (parametric)
sphere = Surface(
    lambda u, v: np.array([
        np.cos(u) * np.cos(v),
        np.sin(u) * np.cos(v),
        np.sin(v)
    ]),
    u_range=[0, TAU],
    v_range=[-PI/2, PI/2]
)

Best Practices

Initialize at creation

Set properties when creating:

# Good
circle = Circle(radius=2, color=BLUE, fill_opacity=0.5)

# Less efficient
circle = Circle()
circle.scale(2)
circle.set_color(BLUE)
circle.set_fill(opacity=0.5)

Reuse when possible

# Good - reuse and transform
circle = Circle()
self.play(Create(circle))
self.play(circle.animate.shift(RIGHT))

# Avoid - creating new objects
circle1 = Circle()
self.play(Create(circle1))
circle2 = Circle().shift(RIGHT)
self.play(Transform(circle1, circle2))

Use VGroups for organization

# Organize related objects
axes_group = VGroup(x_axis, y_axis, labels)
data_group = VGroup(points, lines, curves)

# Easy to manipulate together
axes_group.shift(LEFT * 3)
data_group.set_color(BLUE)

Consistent coloring

Define color schemes:

PRIMARY = BLUE
SECONDARY = RED
ACCENT = YELLOW

title = Text("Title", color=PRIMARY)
shape = Circle(color=SECONDARY)
highlight = Square(color=ACCENT)

Next Steps

Animations

Learn how to animate mobjects

Geometry Reference

Complete geometry API reference

3D Objects Reference

Complete 3D objects API

Examples

See mobject examples

Getting Started

VTK Features

Core Concepts

Examples

Advanced Topics

​What are Mobjects?

​Mobject Hierarchy

​Creating Mobjects

​Basic 2D Shapes

​Basic 3D Objects

​Text and Math

​Mobject Properties

​Color

​Opacity

​Size

​Position

​Rotation

​Styling Mobjects

​Stroke (Outline)

​Fill (Interior)

​Combining Stroke and Fill

​Grouping Mobjects

​VGroup

​Arrangement

​Copying Mobjects

​Mobject Methods

​Common Methods

​Alignment Methods

​Custom Mobjects

​Creating Custom Shapes

​Using Paths

​Surfaces and Parametric Objects

​Parametric Surface

​Common Parametric Surfaces

​Best Practices

​Next Steps

Animations

Geometry Reference

3D Objects Reference

Examples

What are Mobjects?

Mobject Hierarchy

Creating Mobjects

Basic 2D Shapes

Basic 3D Objects

Text and Math

Mobject Properties

Color

Opacity

Size

Position

Rotation

Styling Mobjects

Stroke (Outline)

Fill (Interior)

Combining Stroke and Fill

Grouping Mobjects

VGroup

Arrangement

Copying Mobjects

Mobject Methods

Common Methods

Alignment Methods

Custom Mobjects

Creating Custom Shapes

Using Paths

Surfaces and Parametric Objects

Parametric Surface

Common Parametric Surfaces

Best Practices

Next Steps