Would you like to create a mobile game, but you don’t know where to start? Modeling, rigging and animating, for the first time for a mobile app can prove to be challenging. This guide gives 3 quick tips to follow about prepping your assets before exporting to Unity. By using this tutorial, your game will run on iPhone 4 or higher.
TIP 1: MODELING
● Limit the total number of polygons to 8,000. The 3D assets need to work to their full potential in the mobile app without making the app heavy. This number varies from one project to another but 8,000 is a good guideline for mobile apps running on iPhone 4S and up.
● Always turn backface culling on. Because like all game engines, only one side of the poly face is rendered. And it is important to be able to see if normals are flipped. Especially on objects that get duplicated and mirrored to the other side of the character.
● Turn on your poly count. It is a quick and constant reminder of number of triangles being used. It’s also a good way to see if there are any overlapping or extraneous vertices on the mesh.
TIP 2: RIGGING & ANIMATION
● Limit the total number of joints to 40. The exact number can only be obtained through testing and varies from one app to another but for iOS 4 and above, 40 is a good number to start with.
● Confirm each vertices are only influenced by 4 joints. Unity only recognizes 4 joint influence per vertex, the remaining animations will either be deleted or result in bad translations. Prune out all the extras weights.
● Make sure your joints are oriented correctly. This seems obvious but one incorrect LRA can create a huge mess in Unity.
TIP 3: BEFORE EXPORTING TO UNITY
● Delete history and freeze transform. History and transform information on your mesh will create problems on your export or even later in Unity.
● Check your normals. Before considering exporting, turn on normals and make sure they are turned outwards.
That’s it. I hope that by sharing our experience we the make process a little easier for others.