video/.claude/skills/manimce-best-practices/rules/transform-animations.md

name, description, metadata

name	description	metadata
transform-animations	Transform, ReplacementTransform, and morphing animations	tags transform, replacementtransform, morph, transformfromcopy

Transform Animations

Animations that morph one mobject into another.

Transform

Morphs the source mobject into the shape of the target. The source mobject is modified.

class TransformExample(Scene):
    def construct(self):
        square = Square()
        circle = Circle()

        self.play(Create(square))
        self.play(Transform(square, circle))
        # Note: 'square' now looks like 'circle' but is still 'square'

Important: After Transform, the original variable still references the mobject, even though it looks like the target.

ReplacementTransform

Morphs source into target and replaces the reference. More intuitive for most uses.

class ReplacementTransformExample(Scene):
    def construct(self):
        square = Square()
        circle = Circle()
        triangle = Triangle()

        self.play(Create(square))
        self.play(ReplacementTransform(square, circle))
        # 'square' is removed, 'circle' is now in the scene
        self.play(ReplacementTransform(circle, triangle))
        # 'circle' is removed, 'triangle' is now in the scene

Transform vs ReplacementTransform

# Transform - source variable changes appearance
self.play(Transform(A, B))
# A is still in scene (but looks like B)
# B is NOT in scene

# ReplacementTransform - source is replaced by target
self.play(ReplacementTransform(A, B))
# A is removed from scene
# B is now in scene

TransformFromCopy

Creates a copy of source and morphs it to target. Original remains unchanged.

class TransformFromCopyExample(Scene):
    def construct(self):
        square = Square().shift(LEFT * 2)
        circle = Circle().shift(RIGHT * 2)

        self.add(square)
        self.play(TransformFromCopy(square, circle))
        # Both square and circle are now visible

TransformMatchingShapes

Intelligently matches and transforms corresponding parts.

class MatchingShapesExample(Scene):
    def construct(self):
        source = Text("ABC")
        target = Text("ABCD")

        self.play(Write(source))
        self.play(TransformMatchingShapes(source, target))

TransformMatchingTex

Matches LaTeX parts by their TeX strings.

class MatchingTexExample(Scene):
    def construct(self):
        eq1 = MathTex("a", "^2", "+", "b", "^2")
        eq2 = MathTex("a", "^2", "+", "2ab", "+", "b", "^2")

        self.play(Write(eq1))
        self.play(TransformMatchingTex(eq1, eq2))

MoveToTarget

Pre-set a target state and animate to it.

class MoveToTargetExample(Scene):
    def construct(self):
        square = Square()
        self.add(square)

        # Generate and modify target
        square.generate_target()
        square.target.shift(RIGHT * 2)
        square.target.set_color(RED)
        square.target.scale(2)

        self.play(MoveToTarget(square))

Path Arc Transforms

Control the path of transformation with path_arc.

class PathArcExample(Scene):
    def construct(self):
        dot1 = Dot(LEFT * 2)
        dot2 = Dot(RIGHT * 2)

        self.add(dot1)
        # Transform along an arc
        self.play(Transform(dot1, dot2, path_arc=PI/2))

Chained Transformations

class ChainedExample(Scene):
    def construct(self):
        shape = Square()
        self.play(Create(shape))

        # Chain of transformations
        for target in [Circle(), Triangle(), Star()]:
            self.play(Transform(shape, target))
            self.wait(0.5)

Best Practices

1. Use ReplacementTransform for clarity - More intuitive variable behavior
2. Use TransformFromCopy to preserve original - When you need both visible
3. Use TransformMatchingTex for equations - Better alignment of matching parts
4. Set path_arc for visual interest - Curved paths look more dynamic