cyberbotics / blender-webots-exporter

Blender add-on to export Webots files

Blender to Webots exporter add-on

Blender add-on to export your Blender project to Webots.

Features

• Export your Blender project to Webots
• Define conversion rules in a JSON file
• Support collision export (either generated from the AABB boxes or manually defined)
• Support joint export (linear or rotational with custom parameters including axis, limits, etc.)
• Support the export of any Webots Solid (or derived) node with custom fields (Camera.width, name, etc.).
• Basic support of materials (colors and the base color map) to Webots PBR appearance.

Requirements

• Blender 2.79b
• Webots R2019a.rev1 or later

Installation and Update

Let say $BLENDER_ADD_ON_PATH is the Blender add-on user directory:

• on macOS: export BLENDER_ADD_ON_PATH=$HOME/Library/Application\ Support/Blender/2.79/scripts/addons
• on Linux: export BLENDER_ADD_ON_PATH=$HOME/.config/blender/2.79/scripts/addons
• on Windows:
  • go to Blender / Preferences / File / Scripts and paste C:\Users\username\AppData\Roaming\Blender Foundation\Blender\2.79\scripts. (replace username)
  • for the following steps, use the pasted address as $BLENDER_ADD_ON_PATH.

Install the add-on by applying the following commands:

mkdir -p $BLENDER_ADD_ON_PATH/export_webots
cp __init__.py "$BLENDER_ADD_ON_PATH/export_webots"
cp export_webots.py "$BLENDER_ADD_ON_PATH/export_webots"

Enable the "Webots exporter" add-on in Blender / Preferences / Add-ons / Community.

JSON Conversion File Specifications

The JSON conversion file specifies how to convert the Blender nodes to Webots ones.

If not specified in the parameters, the JSON conversion file is searched in the same path as the .blend file.

It is basically a JSON Object (i.e. key-value associative array) containing a conversion rule for each node. During the exportation, when a key of this JSON Object matches with the slugified Blender node name, then its value (a JSON Object) is used for the conversion.

The conversion JSON Object could contain the following conversion rules:

Key	Flags	Value
target node	required	JSON String defining to which Webots node the Blender node should be converted. For example, it could be Solid, Robot, Camera, HingeJoint, SliderJoint or a custom Webots appearance node (like BrushedAluminium).
fields	optional	JSON Object which can contain any Webots node fields. The conversion tool will add these fields as-is. It is convenient to add device specific fields, like Camera.width, Emitter.name, etc.

The following conversion rules are only available in the case of a Solid node (or derived):

Key	Flags	Value
physics	optional	JSON Object which can contain the Webots Physics node fields (like mass, density and centerOfMass). If this key is not defined, then no Physics node is generated (the Solid can be pinned to the static environment, or controlled using kinematics rules.)
boundingObject	optional	JSON Object which can contain either a JSON String called custom to define the content of the Webots Solid.boundingObject field fields. If custom is not defined, then the AABB box of the Blender object is used to create the boundingObject. If this key is not defined, then no collision object is generated.

The following conversion rules are only available in the case of a Joint node:

Key	Flags	Value
jointParameters	optional	JSON Object which can contain the Webots (Hinge)JointParameters node fields (like axis, spring/dampingConstant and suspension*).
motor	optional	JSON Object which can contain the Webots LinearMotor or RotationalMotor node fields (like name, maxTorque, maxPosition or maxVelocity)
positionSensor	optional	JSON Object which can contain the Webots PositionSensor node fields (like name)

Examples:

https://github.com/cyberbotics/blender-webots-exporter/tree/master/examples

References

This script has been inspired by the Blender X3D exporter of Campbell Barton, Bart, Bastien Montagne, Seva Alekseyev.

blender-webots-exporter's Issues

Support for Blender >= 2.80

Blender unfortunately modified their plugin API in Blender >= 2.80.
This project should be updated accordingly.

cannot enable the "Webots exporter" add-on

When I enable the "Webots exporter" add-on in Blender / Preferences / Add-ons / Community, there is an ERROR!
ImportError: cannot import name 'orientation_helper_factory' from 'bpy_extras.io_utils' (C:\Program Files\Blender Foundation\Blender 2.82\2.82\scripts\modules\bpy_extras\io_utils.py);
It seems that blender has changed quite a few things since v2.80.

Empty appearance DEF names

I was trying to export the blender file below and it did not give me any problems then but when I tried opening it in Webots it gave me:
ERROR: 'C:/Users/***/Documents/Inventor/FRC Field 2019/FRC Field 2019.wbt':17:37: error: Expected node or PROTO name, found '{'.
ERROR: 'C:/Users/***/Documents/Inventor/FRC Field 2019/FRC Field 2019.wbt': Failed to load due to syntax error(s).

I am in Webots R2019b and in Windows 10

https://drive.google.com/open?id=1kuIG4Jh2BoMZ4Qza5nOWXdTzLzb_mli0

Exportation Creates Tessellation Error on some Meshes

When exporting some meshes it sometimes generates self-intersecting faces.
The same mesh exported to VRML works fine.

Here is an example:

• Toilet.1.blend.zip

Exporting to X3D gives the same tesselation errors.

Wrong texture url in case of more than one texture

If more than one texture is defined, the export is wrong:

texture DEF IM_COLOR_MAP ImageTexture {
  url [ ""toilet/map/stargalaxy granite color.jpg" "stargalaxy granite color.jpg" "/home/david/Téléchargements/toilet/map/stargalaxy granite color.jpg"" ]
}

Wrong Texture Export in case of PBRAppearance

In case of PBRAppearance the texture is exported with the 'texture' field and not 'baseColorMap' (https://github.com/omichel/blender-webots-exporter/blob/master/export_webots.py#L388).

Is this still the suggested approach for Webots2022?

We're trying to import a complex model into Webots and we're looking for the best way to do this (model, UV's, etc.). Is this plugin still the suggested approach or is there a new way to do it? It looks like this is out of date.