Question Generating Rig at runtime

Hi,

I want to generate a Rig at runtime once on the Awake function but it does not work. I'm using unity 2019.3.13f1.

Code (CSharp):

1. public class TestRigBuilder : MonoBehaviour
2. {
3.     public GameObject SourceObject;
4.     public GameObject ConstrainedObject;
5.  
6.     RigBuilder rigbuilder;
7.  
8.     private void Start() {
9.         // Add the rig
10.         Rig rig = (Rig)transform.AddChild<Rig>();
11.  
12.         // Add constraint to rig
13.         MultiAimConstraint constraint = rig.gameObject.AddComponent<MultiAimConstraint>();
14.         constraint.data.constrainedObject = ConstrainedObject.transform;
15.         constraint.data.aimAxis = MultiAimConstraintData.Axis.Y;
16.         WeightedTransformArray sources = new WeightedTransformArray(0);
17.         sources.Add(new WeightedTransform(SourceObject.transform, 1f));
18.         constraint.data.sourceObjects = sources;
19.  
20.         // Add rig to rigbuilder
21.         rigbuilder = GetComponent<RigBuilder>();
22.         rigbuilder.layers.Clear();
23.         rigbuilder.layers.Add(new RigBuilder.RigLayer(rig, true));
24.  
25.         // build rig graph (Does not seems to be doing anything)
26.         rigbuilder.Build();
27.     }
28. }
29.  
30. /// <summary>
31. /// Add a child gameobject with the specified component. Returns the added component.
32. /// </summary>
33. /// <param name="transform"></param>
34. /// <returns></returns>
35. public static Component AddChild<T>(this Transform transform) where T : Component {
36.     GameObject gameObject = new GameObject(typeof(T).Name);
37.     gameObject.transform.SetParent(transform);
38.     return gameObject.AddComponent<T>();
39. }

 

Alright, after more testings, it seems like some constraint can be generated at runtime and some can't...

The MultiAimConstraint can't but the BlendConstraint works fine.

Currently trying to figure out the difference between the two on how they are handling specifically the sources transform reference because I have a feeling that's the problem.

Here's the code to my second simplified test with BlendConstraint that works:

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Animations.Rigging;
3.  
4. public class TestRigBuilderParent : MonoBehaviour
5. {
6.     public GameObject SourceObjectA;
7.     public GameObject SourceObjectB;
8.     public GameObject ConstrainedObject;
9.  
10.     RigBuilder rigbuilder;
11.  
12.     private void Start() {
13.  
14.         // create rig gameobject
15.         GameObject rigGameobject = new GameObject("Rig");
16.         rigGameobject.transform.SetParent(transform, true);
17.  
18.         // Add constraint to rig
19.         BlendConstraint constraint = rigGameobject.AddComponent<BlendConstraint>();
20.         constraint.data.constrainedObject = ConstrainedObject.transform;
21.         constraint.data.sourceObjectA = SourceObjectA.transform;
22.         constraint.data.sourceObjectB = SourceObjectB.transform;
23.         constraint.data.blendPosition = true;
24.  
25.         // Add the rig
26.         Rig rig = rigGameobject.AddComponent<Rig>();
27.  
28.         // Add rig to rigbuilder
29.         rigbuilder = gameObject.AddComponent<RigBuilder>();
30.         rigbuilder.layers.Clear();
31.         rigbuilder.layers.Add(new RigBuilder.RigLayer(rig, true));
32.  
33.         // build rig graph (Does not seems to be doing anything)
34.         rigbuilder.Build();
35.     }
36. }

The same test with MultiAim Constraint which does NOT work:

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Animations.Rigging;
3.  
4. public class TestRigBuilderMultiAim : MonoBehaviour
5. {
6.     public GameObject SourceObject;
7.     public GameObject ConstrainedObject;
8.  
9.     RigBuilder rigbuilder;
10.  
11.     private void Start() {
12.  
13.         // create rig gameobject
14.         GameObject rigGameobject = new GameObject("Rig");
15.         rigGameobject.transform.SetParent(transform, true);
16.  
17.         // Add constraint to rig
18.         MultiAimConstraint constraint = rigGameobject.AddComponent<MultiAimConstraint>();
19.         constraint.data.constrainedObject = ConstrainedObject.transform;
20.         WeightedTransformArray sources = new WeightedTransformArray();
21.         sources.Add(new WeightedTransform(SourceObject.transform, 1f));
22.         constraint.data.sourceObjects = sources;
23.  
24.         // Add the rig
25.         Rig rig = rigGameobject.AddComponent<Rig>();
26.  
27.         // Add rig to rigbuilder
28.         rigbuilder = gameObject.AddComponent<RigBuilder>();
29.         rigbuilder.layers.Clear();
30.         rigbuilder.layers.Add(new RigBuilder.RigLayer(rig, true));
31.  
32.         // build rig graph (Does not seems to be doing anything)
33.         rigbuilder.Build();
34.     }
35. }

 

Hi Simon,

I just tried both techniques and it didn't work. I agree with you that there shouldn't be anything different between the MultiAimConstraint and the BlendConstraint but it seems there is one unless I'm missing something. The way the scene is built is the same for both tests I did.

You can find the extremely simplified project with a Scene and the two scripts that generate the Rig/Constraint on Start. One script is for the MultiAim and then the other one is for the BlendConstraint. If you opent the scene and hit Play, you'll see the BlendConstraint works but not the MultiAim Constraint.

Here's the WeTransfer link to the project:
https://we.tl/t-xBeviy5m6f

Thank you yes I'm sure it's not efficient at all but I only want to this operation only once on Start in order for the constraint to work.

Thank you

Daniel

 

Ahh yes! That's what I was looking for! Can't believe I didn't see that settings were all wrong before... I guess I was expecting it to behave like a regular MonoBehaviour.

Thank you for all your help! I have seen other people asking the same question so I'm sure this thread will really help them.

Thank you again Simon! Your a life saver!

 

Would you guys (or someone else) be willing to throw together some documentation on creating runtime rigs with this? -- (i.e. a step-by-step process, for example?)
Sometimes it is not clear the underlying reasons for most of the choices you guys make in your implementations / examples, so this would help plenty of people out to understand the underlying approach a lot better.

I can imagine plenty of people wanting to know how to create runtime rigs in a more straightforward way, myself included, had I not come across this post by accident.

 

I'm looking for the same thing! @danUnity, if you wouldn't mind a quick explanation that goes over the steps, I'm sure we would all really appreciate it!

 

I think I got the process pretty straight. I would like to do a youtube tutorial on that but not sure how soon I will get to it done.

 

Is there any way to create dynamic IK at runtime

 

I cannot tell you how much this helped me out. I wish the documentation was a bit more involved cause I spent hours banging my head against a wall trying to figure out why the constraints weren't working at runtime. It was a simple RigBuilder.Build(); call that saved it all. Thanks!

 

Hi there! When I remove a constraint at runtime and rebuild, my console gets flooded with the following warning messages:

Is there a better practice for removing constraints?

 

Ah just fixed it by calling

AnimatorJobExtensions.UnbindAllStreamHandles(animator);

before building and rebinding!

 

jesus christ, and how casual user should know this??
read the animation manual(animation rigging) and it has zero information about this stuff even the API documentation
great examples of how to use it in scene with already defined character and rig, etc, but basically its for simple prototyping situation, nothing for dynamically loading the character and its items
would be nice to have how-to
reload rig in a proper way
how to add object in character hands and reload the rig properly.(rebuild rebind animator disable enable doesnt work, at least in 2021.3lts didnt work, some handle error.., gonna try with 2022.3lts)