Blenderset is tool for creating synthetic training data using blender. It can be used to create random scenes consisting of a real background image, ontop of which random humans and vehicles models are rendered with random lighting. In addition to the rendered images, annotations are generated in form of pixelwise instance-segmentations and bounding boxes. Here are a few example of images produced using blenderset:

• Create a root directory and enter it: mkdir blenderset; cd blenderset
• Clone the repo: git clone https://github.com/AxisCommunications/blenderset-addon.git
• Create asset and metdata directories: mkdir blenderset-assets blenderset-metadata
• Install system-wide dependencies: sudo apt install libopenexr-dev libimath-dev
• Make sure you have ldconfig in your path. If not: sudo ln -s /sbin/ldconfig /usr/local/bin/
• Make the addon directory your cwd: cd blenderset-addon
• Create and initialize virtual environment: . ./init_env.sh (you might have to make sure that the file is executable with, for example chmod 775 init_env.sh)
• Install dependencies: make sync_env. Addons that crash will simply not show up in the GUI. If some packages can't be installed you can install them manually by running sudo apt install apt-file and then sudo apt-file update, and then you can seach for the missing packages using apt-file search xxx where xxx is the missing package. The missing package can then be installed by eg. sudo apt install libavcodec-dev sudo apt install libswscale-dev

Addons that crash will simply not show up in the GUI.

To use blender set custom assets and corresponding metadata are needed. Depending on what kind of scenes are to be rendered, different types of assets will be needed. By default, blenderset will look for assets in the ../blenderset-assets and ../blenderset-metadata directories. Some example metadata for both free and paied asets are availible in example-assets and example-metadata, which can either be copied to the above dirs or a config file can be placed in ~/.config/blenderset/config.json specifying which diretories to use. For example:

{
    "metadata_dir": "/usr/local/src/blenderset/example-metadata",
    "assets_dir": "/usr/local/src/blenderset/example-assets"
}

Each background consist of:

• A camera image of an empty scene
• A camera model
• A region of interest (ROI) defining where to place pedestrians
• A set of tags used to filter out which backgrounds to use

These are specified in the images_metadata.json file. There is a helper script poly_roi.py that can be used to create the ROI coordinates: python poly_roi.py --file image.jpg --roi-file roi.json, which then needs to be copied into images_metadata.json.

Instead of using a real image as background, the ground plane can be textured with a downloaded material. Material can be found at for example https://polyhaven.com/textures. Select blender as format and unpack the downloaded zip-file in example-assets/polyhaven.

To light the scene HDRIs are used. They can be found at for example https://polyhaven.com/hdris. Select format hdr and place the downloaded files in example-assets/skys.

To add vehicles to the scene, the comercial Transportation Addon from blender marked can be used. Install the addon manually and copy ~/.config/blender/3.2/scripts/addons/Tranportation/data to example-assets/Tranportation_data. It's zip-fle can also be placed in the custom_addons directory to be installed automatically during the normal installation processes.

3D models of humans can be created in Reallusion Character Creator or downloaded from Actorcore. Export them into blender format and place them in example-assets/Character_Creator_v3.41/BlenderCharacters256, and add an entry to example-metadata/character_metadata.json. Also, poses are needed they can be extracted from animations downloaded from for example Actorcore. Export them to blender as .fbx and place the files in example-assets/Character_Creator_v3.41/Animations/Avatar/<avatar>/, where <avatar> is a string specifying which characters the animation can be applied to by looking for the same string in the avatar_base property of the character metadata. Then import them using the import_animation.py, which can be called by make import_animations. This will update the metadata in animations_metadata.json and convert the .fbx files into .blend files.

To try out the example example-metadata/character_metadata.json out of the box:

• Create an account at Actorcore and log in
• "Buy" one or several of the free animations
• Go to Inventory in the top right menu
• Select "Motion" and the motion(s) to download and press "Download"
• Select the "Male Robot", check "Export motion only" and press "Next"
• Select "Blender" and press "DOWNLOAD"
• Extrax the zip file and move the .fbx files into example-assets/Character_Creator_v3.41/Animations/Avatar/MaleRobot/
• Run make import_animations in the blenderset-addon directory
• "Buy" the two free Actors Party_M_0001 and Party_F_0001
• Go to Inventory in the top right menu
• Select "Actor", enable "Multiple Select", chooce the two actors and press "Download"
• Move the two diretories party-f-0001 and party-m-0001 to example-assets/Character_Creator_v3.41/BlenderCharacters256/
• Start blender with make interactive
• Open the "Synthetic" tab on the right hand side of the 3D view
• Press one of the 3 top "Scenario" buttions
• If you want more Characters, press "Create" under "Characters"
• To move the characters and alter the pose, press "Update" under "Characters"