So I want to flip all the red faces into blue from the exterior, but I don’t seem to find anything that will change all the exterior faces to blue. And because of it I can’s open it properly in unity.
Is there any addon or tool that is able to do it?
There’s not currently a way to do it automatically, although I’ve seen some promising possibilities with geometry nodes. Your best bet is to fix it by hand
Alight, thank you.
I actually found a way to do it! You just select all the vertices, press Alt + N and press recalculate outside!!
Glad this worked for you, it often doesn’t 
