A lot of my project start with simple tasks such as create a single specific material, or modeling some assets for kitbash. This one start with a simple door recreation I wanted to kitbashing. And it just went on to be a 8-hours project to create a simple shot.
So yeah, you don’t need to have a crazy and epic idea before starting a personal project, if any, just start from small task. If nothing came along, well at least you will have some assets to support other projects.
Cheers.

