RenderRPO Class Documentation

Overview

The RenderRPO class is designed to render a Relative Positioning Operation (RPO) scenario in space with the Earth, a chaser satellite, and a target satellite using the pyvista and pyvistaqt libraries.

Dependencies

To use the RenderRPO class, the following libraries must be installed:

import pyvista
from pyvista import examples
import numpy as np
from pyvistaqt import BackgroundPlotter
import os
import datetime
import math

Class Definition

class RenderRPO:

    def __init__(self):
        self.timer_count = 0

        self.chaser_stl_path, self.target_stl_path = 'models/DART_STL.stl', 'models/DART_STL.stl'
        self.pl, self.earth, self.chaser_mesh, self.target_mesh = self._BuildScene()
        self.light = self._set_light_position_by_date(datetime.datetime.now())
        self.pl.add_light(self.light)

        self.earthaxis = pyvista.AxesActor()
        self.earthaxis.origin = self.earth.center
        scale = 1000
        self.earthaxis.SetTotalLength(6371+scale, 6371+scale, 6371+scale)
        self.earthaxis.GetXAxisCaptionActor2D().GetCaptionTextProperty().SetColor((1, 0, 0))
        self.earthaxis.GetYAxisCaptionActor2D().GetCaptionTextProperty().SetColor((0, 1, 0))
        self.earthaxis.GetZAxisCaptionActor2D().GetCaptionTextProperty().SetColor((0, 0, 1))
        
        self.pl.add_axes()

        print('Building scene...')
        print('The units of the scene are in km.')
        print('Scene built.')
        print('Rendering scene...')

    def _BuildScene(self):
        earth, earth_texture = self._BuildEci()

        print('Building satellites...')
        print(f'Chaser: {self.chaser_stl_path}')
        print(f'Target: {self.target_stl_path}')
        chaser_mesh, target_mesh = self._BuildSatellites(self.chaser_stl_path, self.target_stl_path)

        pl = BackgroundPlotter(lighting="none")
        cubemap = examples.download_cubemap_space_16k()
        _ = pl.add_actor(cubemap.to_skybox())
        pl.set_environment_texture(cubemap, True)

        pl.add_mesh(earth, texture=earth_texture, smooth_shading=True)
        pl.add_mesh(chaser_mesh, color='red')
        pl.add_mesh(target_mesh, color='blue')

        print('Returning plotter and objects.')
        return [pl, earth, chaser_mesh, target_mesh]

    # ... (Other methods continue in a similar fashion)

Methods

• __init__(self): Initializes the rendering plotter, loads the meshes, and sets up the scene.
• _BuildScene(self): Constructs the visual scene with the Earth, chaser, and target meshes.
• _BuildEci(self): Creates the Earth mesh with texture.
• _BuildSatellites(self, chaser_stl_path, target_stl_path): Loads the STL models for the chaser and target satellites.
• set_chaser_position(self, position_eci): Sets the chaser's position in Earth-Centered Inertial (ECI) coordinates.
• focus_on_chaser(self): Adjusts the camera to focus on the chaser satellite.
• animate(self, update_freq=30): Initiates the animation of the satellites.
• update_scene(self, event): Updates the scene; meant to be called by a Qt timer.
• _distanceFromEarthSurface(self, position_eci): Calculates the distance of an object from Earth's surface.
• _set_light_position_by_date(self, date_time): Sets the lighting based on the current date and time to simulate sunlight.

Usage

To use the RenderRPO class, instantiate it and call the appropriate methods for your simulation needs. Ensure that the models/DART_STL.stl paths are correctly set to the locations of your STL files.

Notes

• The class is designed to work with the pyvistaqt BackgroundPlotter for interactive visualization.
• Error handling for file paths and STL file integrity should be considered when implementing in a production environment.
• The _set_light_position_by_date function is a simplification and may need more accurate astronomical calculations for precise simulations.

Authors

• [Vincent Chen]