Instance

Each object in the scene is an Instance. User can add/delete some instance, or changing the transformation/scale for each instance.

Attributes

Attribute	Type	Description	Default value	Required
id	str	Instance ID, users need to add their own prefix to ensure that the ID is unique	-	Yes
label	int	The label of the instance, indicating the category to which the instance belongs	-	Yes
transform	list	The transformation matrix of the instance, which is a list type of a 4 x 4 matrix transformed according to row first	-	Yes
type	str	Possible values are MESH \| ASSET\| COMPOSITE	-	Yes

Function

Function	Description
set_attr({attr_name}, args, *kwargs)	Set the attributes of the instance, see the name of the instance attributes
set_rotation(rotation_list)	Set rotation of instance. rotation_list: `list`. 3 x 3 matrix converted according to row first list.
set_scale(scale_list)	Set scale of instance. scale_list: `list`. a list of scaling factors
set_position(position_list)	Set position of instance. position_list: `list`. a list of position coordinates.

Get the instance and its attributes

Example

class ReadInstanceDsl(EntityProcessor):
    def process(self):
        # loop all instances
        for instance in self.shader.world.instances:
            label = instance.label

Add instance

Function Description

self.shader.world.add_instance({attr_name}={attr_value}): Create a new instance and add it to the scene

Example:

class AddInstance(EntityProcessor):
    def process(self, *args, **kwargs):
        ins = self.shader.world.add_instance(
            id="test", label=1107, path="meshId", type="ASSET",
            transform=[1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0]
        )

Modify instance properties

Modify the instance transformation matrix

When modifying this attribute, it is achieved by rotating, panning and zooming, and one or more of the following operations can be performed

example:

class SetInstance(EntityProcessor):
    def process(self, *args, **kwargs):
        for ins in self.shader.world.instances():
            ins.set_position(
                [0, 0, 50]
            ).set_rotation(
                [1, 0, 0, 0, 1, 0, 0, 0, 1]
            ).set_scale([1, 1, 1])

For some cases, users want to generate scenes with disorder objects for exploring the generalizations of CV models. This can be easily achieved by using these interfaces, we show an example code below.

import numpy as np
from scipy.spatial.transform import Rotation as R
class DisorderInstance(EntityProcessor):
    def process(self, *args, **kwargs):
        for ins in self.shader.world.instances():
            random_pos = np.array([ins.transform[i] for i in [3, 7, 11]]) + np.random.uniform(-1, 1, size=3) * 10
            random_pos[2] = np.random.random() * self.shader.world.levels[0].height
            ins.set_position(
                random_pos.tolist()
            ).set_rotation(
                np.concatenate(R.random().as_matrix()).tolist()
            ).set_scale(np.random.random(3).tolist())

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