3d anaglyph movies in Blender – bertinireal.anaglypy

The Anaglypy class in bertini_real allows user to render 3d anaglyph movies of algebraic surfaces using Blender/Python API.

Preliminaries

1. Please make sure you are using Python 3.7 (matches with the python version of Blender), have already installed Blender 2.8 and added it to the environmental path.

• MacOS: Install python 3.7.0 from python.org

• Linux (Ubuntu): sudo apt install python3.7

2. Install Blender 2.8 (latest version which uses Python 3.7 interpreter)

• Download and install Blender 2.8

3. Add Blender to PATH:

• MacOS: echo "alias blender=/Applications/blender2.8/blender.app" >> ~/.bashrc

• Linux (Ubuntu): export PATH=/path/to/blender2.8/blender:$PATH

4. Install python packages required by Bertini_real into Blender Python Modules Folder in your local terminal: (use the latest version pip for Python 3.7)

• MacOS: pip3 install -t /Applications/blender2.8/blender.app/Contents/Resources/2.80/scripts/modules <python-package-name> --upgrade

• Linux (Ubuntu): pip3 install -t /path/to/blender2.8/2.80/scripts/modules <python-package-name> --upgrade

• List of python package names
  dill	matplotlib	sympy	scipy	numpy
  algopy	mpmath	trimesh	shapely	cython
  pyopengl	triangle	glumpy	pillow	encodings

5. Other issues:

• If the commands don’t work, add option --system

• For Linux users, if you get error: “command ‘x86_64-linux-gnu-gcc’ failed with exit status 1”, try running this command: sudo apt-get install python3.7-dev or try this solution

• If you get errors such as “pickle.load EOF Error: Ran out of input” related to pickle, try running “pip 3 install dill pillow –upgrade”

MacOS Configuration

1. Make environment modifications

export BLENDER_SYSTEM_PYTHON=/usr/local/lib/python3.7/site-packages

2. Solve the finding of the scripts problem

export BLENDER_SYSTEM_SCRIPTS=/Applications/Blender.app/Contents/Resources/2.80/scripts

3. Add the entire python path to the one in the shell. The paths to add come from getting the system path from the python console INSIDE blender. Type the following commands in the blender python console

import sys

print(sys.path)

4. Clean up the formatting sys.path and replace with colons

5. Then, in the local terminal, export the path from Step 4 (note the escaped space in that line!):

export PYTHONPATH=/Applications/Blender.app/Contents/Resources/2.80/scripts/addons_contrib:/Applications/Blender.app/Contents/Resources/2.80/scripts/addons:/Applications/Blender.app/Contents/Resources/2.80/scripts/startup:/Applications/Blender.app/Contents/Resources/2.80/scripts/modules:/Applications/Blender.app/Contents/Resources/2.80/python/lib/python37.zip:/Applications/Blender.app/Contents/Resources/2.80/python/lib/python3.7:/Applications/Blender.app/Contents/Resources/2.80/python/lib/python3.7/lib-dynload:/Applications/Blender.app/Contents/Resources/2.80/python/lib/python3.7/site-packages:/Applications/Blender.app/Contents/Resources/2.80/scripts/freestyle/modules:/Applications/Blender.app/Contents/Resources/2.80/scripts/addons/modules:/Users/brakeda/Library/Application\ Support/Blender/2.80/scripts/addons/modules

Python Scripting

After done configuring and installing Blender, you can decompose a surface, and automate video rendering process of the surface through a shell script, anaglypy.sh (can be found in bertini_real’s python anaglypy folder) to export 3d stereoscopic movies.

We are using surface Crixxi and Daisy in this example.

Using Shell Scripting

First, create a folder (e.g., data/ ) containing all subfolders of surfaces that you have already decomposed by bertini_real.

Copy anaglpy.json, anaglypy.py and anaglypy.sh located in bertini_real’s anaglypy python folder to the data/ folder you just created.

Remember to change permission of the shell script:

$ chmod 755 anaglypy.sh

You will need four files to automate the video rendering process:

1. anaglypy.json (A JSON file specifying object and video settings)

2. anaglypy.py (A Blender Python API script)

3. anaglypy.sh (An automation video rendering shell script)

4. surfaces.txt (A texfile containing the names of surfaces)

Explanation of anaglypy.json

{

  "anaglyph": 0 | 1 # 0: Non-Anaglyph 3D Effect, 1: Anaglyph 3D Effect
  "raw_smooth": "Raw" | "Smooth" | "Both"
  "animation": "Rotate_Z" | "Rotate_XYZ" | "Spin" | "Multi_Rotate" # Multi_Rotate is only available if raw_smooth = "Raw" or "Smooth")]

  "color": {
    "r": 0 - 255 # red
    "g": 0 - 255 # green
    "b": 0 - 255 # blue
    "alpha": 0 - 1 # opacity of color
  },

  "video_settings":{
    "num_frames": 100 # Number of frames
    "film_exposure": 3.5 # Film exposure
    "file_format": "AVI_JPEG" | "AVI_RAW | "FFMPEG" # Blender Movie File Format
    "color_mode": "RGB" # Color mode
    "views_format": "STEREO_3D" # For stereocopy movies only
  },

  "resolution":{
    "percentage":100 # Percentage scale of render resolution
    "x": 800 # Resolution X
    "y": 700 # Resolution Y
  },

  "object":{ # Single Object
    "dimension": 1.5
    "inflation":0.15
  },

  "object_both":{ # Two Objects
    "dimension": 1.15
    "inflation":0.15
    "location": 1.15
  },

  "object_multi":{ # Three Objects
    "dimension": 1.0
    "inflation":0.1
    "location": 1.65
  },

  "convergence_distance": 11 # Converge point for the stereo cameras
  "interocular_distance":1.5 # Set the distance between the eyes - the stereo plane distance
}

Example: surfaces.txt

crixxi
daisy

Place your files in the following standard structure, for example:

data/
  ├── anaglypy.json
  ├── anaglypy.py
  ├── anaglypy.sh
  ├── surfaces.txt
  ├── crixxi/
  |     ├── BRdata0.pkl
  |     └── ...
  └── daisy/
        ├── BRdata0.pkl
        └── ...

Run this command in the terminal to automate the rendering process:

$ ./anaglypy.sh

It will begin multiple rendering processes accordingly based on the surfaces.txt:

Created avi: render/crixxi_rotate_z_both_non_anaglyph0000-0100_L.avi

Fra:0 Mem:25.35M (0.00M, Peak 25.37M) | Time:00:00.00 | Mem:0.00M, Peak:0.00M | Scene, View Layer, left | Synchronizing object | crixxi

....

Export Anaglyph 3D crixxi_rotate_z_both_non_anaglyph.avi  successfully

Created avi: render/daisy_rotate_z_both_non_anaglyph0000-0100_L.avi

Fra:0 Mem:25.35M (0.00M, Peak 25.37M) | Time:00:00.00 | Mem:0.00M, Peak:0.00M | Scene, View Layer, left | Synchronizing object | crixxi

....

Export Anaglyph 3D daisy_rotate_z_both_non_anaglyph.avi  successfully

These are the exported videos from this example:

Finally, you can find all videos and blender files in a newly created folder render/ in each surfaces subfolder.

Examples of video output

Here’s a gallery of 3d anaglyph and non-anaglyph algebraic surface animations!

Author

Foong Min Wong

Version

1.0 2019/07/18