QtThree

A (very much) simplified version of the Three.js 3D editor written with PySide2 and PyQtGraph.

Requirements

Python 3.7+
Python OpenGL bindings (windows/osx / linux)

Setup & Usage

I recommend setting up a virtual environment for installation.

$ pip install -r requirements.txt
$ python -m qtthree

Project Design

Please read below for all of my design decisions relating to the development of this project.

Rendering

Rendering of the scene is handled via PyQtGraph's OpenGL widget.

Object Transformation

Transformation of objects is maintained internally by PyQtGraph's Transform3D class. This class is simply an extension of Qt's QMatrix4x4 with some additional helper methods.

The QMatrix4x4 class, and by extension the Transform3D, make it very simple to rotate and laterally transform objects.

In-Memory Object Storage

Internally, objects are all written as a subclass of an AbstractShape. This base class provides helper methods that can be easily modified to include the additional fields implemented by the inhereting classes. This also enables shape classes to be easily serialized without the duplication of code.

For instance, a Box is an extension of the AbstractShape with length, width, and height fields added.

Serialization

Serialization for shape properties hooks into the event handlers for the property field updates. Whenever a field is edited, the Serializer method is called. In order to prevent excessive file I/O, debouncing is implemented on the method to save a shape.

For simplicity, I chose to store persistent data in JSON format. It would be just as feasible to use a SQL database to store shape data. Using a SQL database would very likely be more efficient and faster.

Custom Shapes

Custom shapes can be loaded via STL files. These files are not stored by the application. For persistence, the location of the selected file is stored. Rather than Boxes and Spheres (which have attributes which can directly modify their meshes), it would be impossible to setup attributes like these for custom shapes. So, in order to modify custom shapes, users can modify the scale.

Type-Hinting

Originally, everything written was type-hinted, but the codebase was littered with type: ignore, simply because the typings for PySide2 are not that great. Type validations were failing, even though the code was correct. I've decided to disable Python type-checking in my workspace due to the poor typings of PySide2.

Linux Python OpenGL Bindings

Installing the Python OpenGL bindings is dependent on your distribution.

Please refer to your package manager's version of the python-opengl package.

tylergibbs2 / QtThree