Replacing Mesh In SkinnedMeshRenderer Causes Deformation

Hi All.

We have a system to replace parts of a character in order to produce the effect of an outfit change.

All of our characters use the same rig, and the same avatar. The problem we are facing is a deformation of the replacement mesh that is assigned at either runtime or in editor, which only happens if we DO NOT have "Optimize Game Objects" checked. Below in the screen shot you can see 2 instances of the same model, with the same replacement mesh assigned. The one on the left is completely deformed, this is the one without the "Optimize Game Objects" checked. The one on the right, which has the option checked, works perfectly.




I'd like to get some insight as to why this is happening, and what can be done (perhaps via script?) to make the non - optimized version work when replacing the mesh.

* By replacing the mesh I mean assigning a different mesh object onto the mesh property in editor, or into the sharedMesh property at runtime.
* We cannot use the "Optimize Game Object" option, as it is unsupported by FinalIK, which we need to use in the project.

 

I think this is caused by the original character being setup as non-optimized, so the replacement meshes need to match the import settings of the original character mesh - either optimized or not.
I'm not 100% positive about this, but I believe this was the solution which resolved a similar issue I encountered.

 

Thanks for the reply. Unfortunately, this isn't the case, as I stated in the OP, all characters share the same avatar. You can only setup the optimization in the import settings of the Rig part of the original avatar, so when shared, there is no way to setup different settings.

 

Yes - you are correct, my mistake.

 

I'm getting the same issue.
Anyone had the same problem?

 

Yep, It seems that the bone order is completely different, which must be the issue.

 

It's great you found the problem. Sorry I couldn't help, I couldn't replicate the problem.

@superpig What causes the bone order change and what is the fix?

 

@superpig - I'm wondering if re-numbering the bones will mean that we have to re-number the boneWeights as well to accommodate?

 

@skalev - if it is the exact same rig how is the bone order changing?
Sorry - there seems to be a little info that is missing - why is the bone order is changing? Is there an extra bone in the chain for the clothing, just for placement or something, but does not have any vertex influence?

 

The bones are the same. The order is different. The modeler is assuming that perhaps minor changes between exports change instanceIDs and causing the order to change.

 

I wrote a test code.
SkinnedMeshUpdater.cs

 

Works like a charm.

 

I've continued the discussion here: http://forum.unity3d.com/threads/as...sh-renderer-bone-index-reorder-problem.401872

As it relates more to reordering bones on asset import. Be grateful if anyone checks it out!

 

For me it worked like this:

Code (CSharp):

1. public Mesh femaleMesh;
2. public Mesh maleMesh;
3.  
4.  
5.  
6.  
7.   public void SelectGender(string gender)
8.     {
9.         switch (gender)
10.         {
11.             case "male":
12.                 avatarObject.GetComponentInChildren<SkinnedMeshRenderer>().sharedMesh = maleMesh;
13.                 break;
14.             case "female":
15.                 avatarObject.GetComponentInChildren<SkinnedMeshRenderer>().sharedMesh = femaleMesh;
16.                 break;
17.         }
18.     }

 

Hey guys, sorry to bump the thread but in case someone is suffering with this I have a solution that might help.
I thought my problem had anything to do with the weights, or anything like this but for me that wasn't making any sense since I was changing the mesh for a mesh that was binded with the exactly same bones (and their respective names), it is even in the same prefab under the same animator. But still, I was getting the skinned mesh renderer to deform my mesh.
Turns out the problem was with the skinned mesh renderer 'bones' property, even if they share the same skeleton, we need to update their bones because they might use or not the same bones of the mesh that was originally there in the skinned mesh renderer. What I did was this:

Code (csharp):

1.  
2. private void ReplaceBones(SkinnedMeshRenderer origin, SkinnedMeshRenderer target, Transform skeletonRoot)
3.         {
4.             Dictionary<string, Transform> allBones = new Dictionary<string, Transform>(); // you can just cache this (and consequently the foreach below) or pass through parameter if in a static context. Leaving here for simplicity
5.             var childrenBones = skeletonRoot.GetComponentsInChildren<Transform>();
6.             foreach(Transform b in childrenBones)
7.             {
8.                 allBones.Add(b.name, b);
9.             }
10.             var originBones = origin.bones;
11.             var targetBones = new List<Transform>();
12.             foreach(Transform b in originBones)
13.             {
14.                 if(allBones.TryGetValue(b.name, out var foundBone))
15.                 {
16.                     targetBones.Add(foundBone);
17.                 }
18.             }
19.             target.bones = targetBones.ToArray();
20.         }
21.  

That way we can tell the skinned mesh renderer which bones should be used by the new Mesh. Btw: In this case you will need the reference for the skinned mesh renderer that carries the mesh that you are swapping to, it is there the info we need: the name of the joints we need to find instantiated. I don't know about swapping by a mesh that was binded with different bone names, maybe that would required a map telling which bone name is which in the new hierarchy structure.

Thanks!

 

Well done. One suggestion though: could you make this into a Unity package so that I can see it in action? I am confused by the code.

 

Excellent solution, I had this problem for years.
But you should create an Editor script ithat makes the changes permanent.

 

Thank you, I have been thinking about this for ages - I had to transfer everything over from each character and have been putting it off for ages, you have saved me so much time.

Just putting the new skinnedmeshrenderer component into the script on the root object in the 'original' field and:

Code (CSharp):

1.    private void Start()
2.     {
3.         UpdateMeshRenderer(original);
4.     }

worked brilliantly. Will get it working to swap selections at runtime.

 

I also encountered the same problem, but I ultimately found that this problem can be solved by selecting the variant mode when creating the prefabricated body, so that the prefabricated body always applies mesh change data. I don't know if it will be helpful to you.

 

this script works wonders, the only little problem, is the height doesnt change one character was taller than the other