Tutorial: Unity - Alpha sorting Issue Fix

We recently switched to Unity 3D and since we are using a lot of rigged and animated 3D planes with alpha blend (since any cutout is extremly expensive on the iPhone). I stumbled upon a issue with this being that the planes got sorted really odd but I also found a fix for this. Some people have requested this tutorial on how to fix this and here it is, english isn't my main language so you will have to bare with me.

I'm using Autodesk Maya but this should translate into other 3D softwares as well since all of them have some function to the same thing as I will show you here. I will show you the problem first and then the solution afterwards.



THE PROBLEM

Here is one of our characters and as you can see he is split up into several parts that are mapped on planes. These planes are then placed behind each other in a very tight space (as you can see on down in the right corner). And if you check the Hypergraph Hierarchy all these parts are separated, but this is not wanted in a 3D engine since this will cost more than combining all parts into one mesh.

 

So before exporting I just combine all these meshes into one and export into Unity (I usually export as .mb) and below are the results. Not that great, the head is behind the body and the banjo is behind that with the strings on top. Not that ecstatically pleasing. So now I will show you the steps to fix this.

STEP 1.
So back to Autodesk Maya where we started, with the character in separate meshes. Make sure to delete all history so there isn't any old stuff in there.

STEP 2.
The next step is to triangulate all parts so we are sure the vertexes are ordered correctly. Delete history after you are done.

STEP 3.
Now the last and trickiest part. You will have to combine the parts two at a time from back to fourth. So for instance, I want the feet to be sorted behind everything else so I combine these two first. Then both feet will become one mesh that I will combine with the body. Then the body and feet will become one mesh that I combine with the Banjo.

My order I combined in with this character:
1. fot with fot
2. mesh from step 1 with body
3. mesh from step 2 with banjo
4. mesh from step 3 with banjo strings
5. mesh from step 4 with arm 1
6. mesh from step 5 with arm 2
7. mesh from step 6 with head
8. mesh from step 7 with hatfeather
9. DELETE HISTORY
10. Rename and export mesh

Then I export the mesh into Unity and here are the results! VOILA! No more alpha sort issues, the meshes work perfect if you rig them with bones and animate them as well as with lightmapped shaders etc.

Holidays are over

So we are full at work again after the holidays. Into the Void is coming together quite nicely, we added a few powerups this week and I started working on the menues.

Our other project have gone through some iterations and is starting to look quite nice, a few more weeks and we might have something to show :)

Back to work..

The critical Artist

We finished up the last fixes on Into the Void for the Christmas Alpha testing. I also went haywire as every artist does and remade all backgrounds to another style.. It looks better :P

//Mr Artist

Almost Christmas

We are working away on our larger project that hasn't gotten a proper name yet. Harald is working on a minigame that is starting to play great and Kristofer is working on our main feature that is soon up and running.

I am finishing up the last things for our first world. I must say each world contains a whole butt-load of art assets. We have never made a game this full of content before, the 20mb wifi limit is loooong gone :P

This evening we will be finishing up the last things on Into the Void before we go on Christmas vacation.

//David Mr.Artist

Saturday slowday

We are working away on Into the Void today, it is a bit slow since there was open house on wednesday and christmas party on thursday. In conclusion, we are beaten down heroes this weekend.

I have been polishing up some backgrounds and effects while Harry is fixing up some bugs and adding some smaller features so we have something to show our families this christmas, we don't want them to think that we are playing around all day (even though we are).

Again, if someone wants to sign up as beta/alpha tester contact me at david@visualdreams.se

//David - Mr.Artist

Clean up

We came to work today and Kristofer was halfway through a new feature (it is an awesome feature :P) and we then realised that our game coordinates differed from my art programs coordinates so we had to fix it. So this day have been filled with mind ****ing of mirrored models and wrong side cullings but now the game is alive and kicking again. It is coming together nicely, in a few weeks we will probably have a nice playable demo available for testing.

A new update for Slam Dunk Basketball surfaced this weekend as well (iOS) that reworked the ads (no more ads during gameplay, whoo) and it now supports Kiip where you can win rewards by completing goals etc.. Try it out!

Into the Void weekend work

We are today working away a few hours on Into the Void. I am working on a few special enemy types and Harald fixed some bugs and added a camera vibration funktion to the game. The list of features is shrinking steadily and it feels great. We tweaked the control a little bit as well, feels much much better now.

//David - Mr.Artist