Hello,
I’m still far from being a game developer. I only started learning Unity a few days ago. However, I’m a professional graphic designer, so instead of using pre-made assets, I prefer to create my own.
But from the moment I started, there’s been a problem I haven’t been able to solve.
Initially, I created an isometric 2D project, and my goal was to first understand relatively simpler things like tilemaps, palettes, and map design — at least simpler for me — before dealing with more complex puzzles like game mechanics and character controls.
However, as always, learning by just watching tutorials isn’t a very realistic method.
In almost every tutorial, the instructor just says, “Click here, open that, add this,” without ever explaining why they are doing those steps.
For example, when starting a project, some tutorials choose SRP Universal 2D Core, while others pick 2D Built-in Render Pipeline Core, but they never explain why they make that choice.
They just say, “Select this.” Okay then. 
Anyway, as a designer, I’m not afraid of learning a new program, but clearly, it’s not very effective to just rely on AI or video lessons.
Of course, I am learning some things, but it’s mostly memorization — I know what to do, but I don’t know why I’m doing it.
And because of that, I’ve been stuck on my first real problem for days now.
I drew a 256 x 256 px ground asset. Before importing it into the game as a PNG, I checked it in Adobe Illustrator to make sure there were no issues when tiled side by side — and there were none. It tiles perfectly.
However, when I import the asset into the game, thin lines appear between the tiles, as you can see in the screenshot.
It looks like each tile has a thin border on top.
I’ve been researching this for the past few days and tried everything GPT and others suggested, but the problem persists.
Can someone explain to me clearly how to solve this issue?
Thank you.
