|Notice the difference in the lighting.|
|Notice how all the lighting is the same.|
So maybe you're having this problem with your mod, and you're wondering 'how do I fix this?' Well good luck buddy.....
JUST KIDDING. Here's how to do it, please note, I purposefully created bad mesh for this example, please don't do things badly just so you can try and automatically fix the problems, 'cause it doesn't always work.
|Here are my two meshes.|
In the above image we have two simple slopes, these are the two that we saw in the first picture, the slope on the left has bad normals, notice how it is a little darker than it's counterpart.
This will work for most things, but what if Blender is setting some faces the wrong way? well then select those faces and click the Flip Direction button located directly below the Recalculate button and Blender will only flip the direction of the selected faces.
Hopefully this helps somebody out, you know who you are. :D Any questions don't hesitate to leave a comment, hit me up on G+ or send me an email. If you'd like a video version just let me know and I'll see what I can make happen.