So, I finished my character and gave it a shirt and pants, but the shirt and pants have no thickness, so when I exported them to unity (thats the game engine I use) and looked inside one of the sleeve holes, You couldn’t see the outside. I actually tried thickening the clothes but the insides were glitching through the outside when I rigged it so I decided to skip that.
Is there a way to stop it from being transparent?
Check to see if you clicked “backface culling” in the materials panel. If so, disable it.