VTK Export - ManimVTK

Introduction

ManimVTK allows you to export your animations to VTK (Visualization Toolkit) file formats, enabling visualization in ParaView, PyVista, and other scientific tools.

VTK export works with any renderer - you can use Cairo, OpenGL, or VTK renderer and still export to VTK formats.

Export Methods

Static Export (Final Frame)

Export the final state of your scene:

manimvtk -pqh scene.py MyScene --vtk-export

Output formats:

Single mobject → .vtp (VTK PolyData)
Multiple mobjects → .vtm (VTK MultiBlock Dataset)

Time Series Export (All Frames)

Export every frame as a VTK file:

manimvtk -pqh scene.py MyScene --vtk-time-series

Output:

.pvd - ParaView Data collection file
.vtp files - One per frame
viewer.html - Basic HTML viewer template

Time Series Guide

Detailed guide on time series export

File Formats

VTK PolyData (.vtp)

Used for single objects with points, lines, and polygons. When created:

Scene contains a single mobject
Explicitly exporting one mobject

Structure:

<VTKFile type="PolyData" version="1.0">
  <PolyData>
    <Piece NumberOfPoints="N" NumberOfPolys="M">
      <Points>...</Points>
      <Polys>...</Polys>
      <PointData>
        <DataArray Name="Colors" .../>
      </PointData>
    </Piece>
  </PolyData>
</VTKFile>

Example output:

media/vtk/MyScene/
└── MyScene_final.vtp

VTK MultiBlock (.vtm)

Used for scenes with multiple objects. When created:

Scene contains multiple mobjects
Complex hierarchical structures

Structure:

<VTKFile type="vtkMultiBlockDataSet">
  <vtkMultiBlockDataSet>
    <DataSet index="0" file="Circle_0.vtp"/>
    <DataSet index="1" file="Square_1.vtp"/>
  </vtkMultiBlockDataSet>
</VTKFile>

Example output:

media/vtk/MyScene/
├── MyScene_final.vtm
├── Circle_0.vtp
└── Square_1.vtp

Basic Examples

Export a Simple Shape

from manimvtk import *

class CircleExport(Scene):
    def construct(self):
        circle = Circle(radius=2, color=BLUE, fill_opacity=0.5)
        self.play(Create(circle))
        self.wait()

manimvtk -pql scene.py CircleExport --vtk-export

Output: media/vtk/CircleExport/CircleExport_final.vtp

Export Multiple Objects

from manimvtk import *

class MultipleShapes(Scene):
    def construct(self):
        circle = Circle(radius=1, color=BLUE).shift(LEFT * 2)
        square = Square(side_length=1.5, color=RED)
        triangle = Triangle(color=GREEN).shift(RIGHT * 2)
        
        self.play(
            Create(circle),
            Create(square),
            Create(triangle)
        )
        self.wait()

manimvtk -pql scene.py MultipleShapes --vtk-export

Output:

media/vtk/MultipleShapes/
├── MultipleShapes_final.vtm
├── Circle_0.vtp
├── Square_1.vtp
└── Triangle_2.vtp

Export 3D Surfaces

from manimvtk import *
import numpy as np

class SurfaceExport(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=(50, 50),
        )
        surface.set_color_by_gradient(BLUE, RED)
        
        self.set_camera_orientation(phi=60 * DEGREES, theta=30 * DEGREES)
        self.play(Create(surface))
        self.wait()

manimvtk -pqh scene.py SurfaceExport --renderer vtk --vtk-export

Export Location

By default, VTK files are saved to:

media/vtk/<SceneName>/

The location follows ManimVTK’s standard media directory structure:

media/
├── videos/
│   └── scene.py/
│       └── 1080p60/
│           └── MyScene.mp4
└── vtk/
    └── MyScene/
        ├── MyScene_final.vtp
        └── MyScene_final.vtm

Programmatic Export

You can also export VTK files programmatically:

from manimvtk import *
from manimvtk.vtk import VTKExporter

class ProgrammaticExport(Scene):
    def construct(self):
        circle = Circle(radius=2, color=BLUE)
        self.add(circle)
        
        # Create exporter
        exporter = VTKExporter(
            output_dir="custom_output",
            scene_name="MyCircle"
        )
        
        # Export single mobject
        exporter.export_mobject(circle, filename="circle.vtp")
        
        # Export scene (all mobjects)
        exporter.export_scene_static(self.mobjects)

Data Preservation

Colors

Mobject colors are preserved in VTK export:

circle = Circle(radius=1)
circle.set_color(BLUE)  # Exported as RGB values
circle.set_opacity(0.5)  # Exported as opacity

In VTK, colors are stored as PointData arrays named “Colors” with RGBA values.

Geometry

Different mobject types are converted appropriately:

Mobject	VTK Representation
Filled shapes	Polygons (triangulated)
Stroked shapes	PolyLines
Surfaces	Polygonal mesh
Text/Tex	Filled paths (polygons)

Transformations

All transformations (position, rotation, scale) are applied before export:

circle = Circle()
circle.shift(RIGHT * 2)  # Position
circle.rotate(45 * DEGREES)  # Rotation
circle.scale(1.5)  # Scale

# All transformations are baked into exported geometry

Advanced Features

Scalar Fields

Attach scalar data to exported geometry:

from manimvtk import *
from manimvtk.vtk import add_scalar_field
import numpy as np

class ScalarFieldExport(Scene):
    def construct(self):
        # Create surface
        surface = Surface(
            lambda u, v: np.array([u, v, u**2 - v**2]),
            u_range=[-2, 2],
            v_range=[-2, 2],
            resolution=(30, 30)
        )
        
        self.add(surface)
        # Export and add scalar field in post-processing

See Scalar Fields for details.

Vector Fields

Attach vector data for flow visualization:

from manimvtk.vtk import add_vector_field

# Add velocity vectors to exported polydata
add_vector_field(polydata, "velocity", velocity_array)

See Vector Fields for details.

Viewing Exported Files

ParaView

Open ParaView
File → Open
Select .vtp, .vtm, or .pvd file
Click “Apply” in the Properties panel

ParaView Guide

Detailed ParaView visualization guide

PyVista (Python)

import pyvista as pv

# Load exported file
mesh = pv.read('media/vtk/MyScene/MyScene_final.vtp')

# Visualize
mesh.plot(
    color='lightblue',
    show_edges=True,
    window_size=[800, 600]
)

# Or interactive
mesh.plot(jupyter_backend='trame')

vtk.js (Web)

import vtkXMLPolyDataReader from '@kitware/vtk.js/IO/XML/XMLPolyDataReader';

const reader = vtkXMLPolyDataReader.newInstance();
reader.setUrl('MyScene_final.vtp');
reader.loadData().then(() => {
  const polydata = reader.getOutputData();
  // Render with vtk.js
});

Best Practices

File Sizes

VTK XML formats are human-readable but can be large. Considerations:

Use compression in ParaView: File → Save Data → check “Compressed”
Lower resolution for testing: resolution=(20, 20) instead of (50, 50)
Use binary format for production (requires VTK binary writer)

Organization

Keep exports organized:

project/
├── scenes/
│   ├── scene1.py
│   └── scene2.py
└── media/
    └── vtk/
        ├── Scene1/
        └── Scene2/

When to Use Static vs Time Series

Use static export when:

You only need the final result
Creating static visualizations
File size is a concern

Use time series when:

Analyzing animation in ParaView
Need frame-by-frame data
Creating interactive temporal visualizations

Performance

Export adds minimal overhead:

Cairo/OpenGL rendering time: ~90%
VTK export time: ~10%

Time series export is slower due to per-frame I/O.

Troubleshooting

Export file not created

Possible causes:

Forgot --vtk-export flag
Scene has no mobjects
Permission issues in output directory

Check:

ls -la media/vtk/

ParaView won't open file

Possible causes:

VTK file corrupted
ParaView version too old

Solution:

Re-export the file
Update ParaView to 5.9+
Check file with text editor (XML should be valid)

Colors missing or wrong

Cause: Color data not exported correctlyCheck:

Are colors set before rendering?
Does the mobject have a stroke or fill?

# Ensure colors are set
circle.set_color(BLUE)
circle.set_fill(BLUE, opacity=0.5)

Next Steps

Time Series Export

Learn about frame-by-frame export

ParaView Guide

Visualize exports in ParaView

Scalar Fields

Add scientific data fields

Examples

See scientific visualization examples

​Introduction

​Export Methods

​Static Export (Final Frame)

​Time Series Export (All Frames)

Time Series Guide

​File Formats

​VTK PolyData (.vtp)

​VTK MultiBlock (.vtm)

​Basic Examples

​Export a Simple Shape

​Export Multiple Objects

​Export 3D Surfaces

​Export Location

​Programmatic Export

​Data Preservation

​Colors

​Geometry

​Transformations

​Advanced Features

​Scalar Fields

​Vector Fields

​Viewing Exported Files

​ParaView

ParaView Guide

​PyVista (Python)

​vtk.js (Web)

​Best Practices

​Troubleshooting

​Next Steps

Time Series Export

ParaView Guide

Scalar Fields

Examples

Introduction

Export Methods

Static Export (Final Frame)

Time Series Export (All Frames)

File Formats

VTK PolyData (.vtp)

VTK MultiBlock (.vtm)

Basic Examples

Export a Simple Shape

Export Multiple Objects

Export 3D Surfaces

Export Location

Programmatic Export

Data Preservation

Colors

Geometry

Transformations

Advanced Features

Scalar Fields

Vector Fields

Viewing Exported Files

ParaView

PyVista (Python)

vtk.js (Web)

Best Practices

Troubleshooting

Next Steps