How do I find out if a shirt Id uses -1 or -2 to find the asset? when loading a shirt into a shirt template in game via script
You mean like this?
Workspace.Player.Shirt.Texture = "http://www.roblox.com/asset/?id=" --Insert shirt asset ID
If you're asking how to find the actual ID of the asset, just keep subtracting 1 from the ID until it works fine. There's no actual way to tell. Otherwise, I don't know what else you're asking.
If you have any other problems, feel free to inbox me.
~Kyo-Chan
If you want to find the shird ID, go to the link of the shirt and subtract 1 from the last number in the ID. The number you are keft with is the shirt template.
Example:
12345678 - ID of the shirt in the link 12345677 - Shirt template ID