Missing part of the object

Questions & Answers
1

I've read answers about a similar problem: normals.

I'm using max, and I've applied an Edit Normals modifier to see them.. but I con't understand which normals I have to modify, no one is really facing something. Can you help me?

If I import the same model using just a material with a unique texture, the model is showed perfectly in Unity.

2

Ok, found how to do it! Thanks anyway.

If someone need the same thing: Edit Normals -> select by face -> select everything then using the select and move, move them to the top. I'll work!