README.md

Object selection and manipulation

In this example we demonstrate how to select entities in the scene using getter.Entity and then manipulate them using the EntityManipulator module.

Usage

Execute this in the BlenderProc main directory:

python run.py examples/basics/entity_manipulation/config.yaml examples/resources/scene.obj examples/basics/entity_manipulation/output

• examples/basics/entity_manipulation/config.yaml: path to the configuration file with pipeline configuration.
• examples/resources/scene.obj: path to the object file with the basic scene.
• examples/basics/entity_manipulation/output: path to the output directory.

Visualization

Visualize the generated data:

python scripts/visHdf5Files.py examples/basics/entity_manipulation/output/0.hdf5

Steps

• Loads scene.obj: loader.ObjectLoader module.
• Creates a point light: lighting.LightLoader module.
• Sets two camera positions: camera.CameraLoader module.
• Selects objects based on the condition: manipulators.EntityManipulator module.
• Change some parameters of the selected entities: manipulators.EntityManipulator module.
• Renders rgb, normals and distance: renderer.RgbRenderer module.
• Writes the output to .hdf5 containers: writer.Hdf5Writer module.

Config file

EntityManipulator

    {
      "module": "manipulators.EntityManipulator",
      "config": {
        "selector": {
          "provider": "getter.Entity",
          "check_empty": True,
          "conditions": {
            "name": 'Suzanne',
            "type": "MESH" # this guarantees that the object is a mesh, and not for example a camera
          }
        },
        "location": {
          "provider": "Uniform3dSampler",
          "max":[1, 2, 3],
          "min":[0, 1, 2]
        },
        "rotation_euler": [1, 1, 0],
        "cp_physics": True
      }
    }

The focus of this example is the EntityManipulator module and getter.Entity which allow us to select multiple entities based on a user-defined condition and change the attribute and custom property values of the selected entities.

• selector - section of the EntityManipulator for stating the chosen provider and the condition to use for selecting.

Our condition is: "name": 'Suzanne' and "type": "MESH", which means that we want to select all the objects with obj.name == 'Suzanne' and which are of "type": "MESH". In our case we have only one object which meets the requirement. Yet one may define any condition where key is the valid name of any attribute of entities present in the scene or the name of an existing custom property. This way it is possible to select multiple objects. One may try this condition to try multiple object selection: "location": [0, 0, 0] With the check_empty key, we can ensure that an error is thrown, when no object was found. The default here is False, meaning that if no object fulfills the condition the EntityManipulator is skipped.

NOTE: any given attribute_value of the type string will be treated as a REGULAR EXPRESSION, so "name": 'Cylinder.*' condition will select us all three cylinders in the scene.

For possible attribute_name's data types check provider.getter.Entity documentation.

After selector section we are defining attribute name and attribute value pairs in the familiar format of {attribute_name: attribute_value}. If attribute_name is a valid name of any attribute of selected object(s), its value will be set to attribute_value. If attribute_name is a name of an existing custom property, its value will be set to attribute_value. If attribute_name is not a valid name of any attribute nor it is a name of an existing custom property, it will be treated as a name for a new custom property, and its value will be set to attribute_value.

In our case we sample the location attribute's value of the selected object using Uniform3d sampler, set the value of the rotation_euler attribute to [1, 1, 0], and create new custom property physics and set it's value to True. By default for each selected object defined samplers will be called. If one wants to have values sampled once and have them set to defined attribute/properties, set "mode": "all" at the end of this section.