STL Viewer
STL files are commonly used in 3D printing, and are easy to generate in code. One project idea I have in mind is to use Rust to generate files for 3D printing on the users web browser. It would be nice if the pipeline was:
User Configuration --> STL --> Preview Rendering
|
V
Download files
This way you can be sure that what the user (and developer) sees is what ends up being created.
One part of this project is to develop a renderer that takes in STL files and allows the user to rotate the view around them.