You might be better off using different objects for things like rocks.
Tile Maps generally imply that you would have contiguous tiles.
Thanks for your fast reply.
For the rocks and other "small things", I was planning to overlay tilemaps (1 for the floor, with solid collision, 1 for the "background" with rocks, trees, flowers...). It will allows me to create huge maps way faster than drag'n'drop objects 1 by 1.
Actually I have 2 questions/notes.
1°) My map will be huge, and I read on this forum that put many sprites for the decor (like dozens and dozens of flowers, rocks, trees, bees...) will create performance issues. When you look on Kiwi Story demo from C3, they use the same things as me, except that there are in pixel art style, mine is more realistic + HD. So, I wonder what is the problem ?
2°) A tilemap SHOULD NOT have obligatorely contiguous tiles. A tilemap is commonly made like mine, as you can see when you search on Google or on assets big library like OGA or Unity asset store. I'm not saying it's the good way, but I assume that if there is so many like this, like the Kiwi Story forest Tilemap object, it means it's not that bad and should work, whatever the graphic style and pixel ratio ?
Thanks again for you time. :-)