Here it is, I have finally finished Skeletal Animation. It has been a long time coming but I have polished it off at last.There were a couple of things that tripped me up and I managed to spot them by simplifying everything down and using a basic 3D model of a cylinder with just three bones, bending in one direction. This is some advice I would give to anybody that is trying to implement this. I think one of the main reasons I didn't do this to start with is purely because of the amount of time it would have taken me(I attempted it a few times in Blender). I had to bite the bullet eventually but I created it in 3DS Max and had it created within about 10 minutes. Just goes to show you the difference between an intuitive and non intuitive UI design. If anybody wants a copy of this model it is here:

Here is the Collada Version and the 3DSMax Version

The two bugs I found were both to do with assimp in some way. Firstly there was a flag I had set for the importer "aiProcess_FindInvalidData" which was causing any Keys from ym keyframes to only appear once if they were the same through the entire animation. After changing this the animation was almost perfect but a few of the bones were still off quite a bit.

This comes to the second issue I had which was from the assimp documentation telling me that the transformations for the Key Frame should be applied as: Scale * Rotation * Translation, when in actual fact I had to change it to Translation * Rotation * Scale. 

Anyway enough of my ramblings, here is the finished product that shows the model finally animating correctly:

This project has taken me quite a long time and I think that if I had just simplified it all much earlier on then this would have been done much sooner. Whilst doing this I noticed that debugging the matrix data for the animation was actually rather complex. This was due to the fact that keyframes aren't stored as Matrices so the only thing you can really check is the positions. I am hoping to put together a simple application at some point that will allow the user to load a model with animations and then be able to check the data assocciated with any bone at any point in time. This will hopefully make other peoples debugging much simpler as they will have a correct version of the running animation with the key frame data exposed for them to compare against their own version.

Okay so this isn't quite the end yet, there is still plenty more to do. Next few things on my list are:

• Tidy up all the animation code
  
• Do some testing on various file formats to ensure they work
  
• Add support for blending multiple animations
  
• Do some performance testing and see how I can make the animation more efficient
  
• Look into ways to incorporate the animation with player input
  

Once all these things are done I can look into either creating a squash player or outsourcing to an artist and get them to create the player and all its animations, which is a much better option. 

Cheers :)

As a quick test on the transformation hierarchy and the vertex weights I decided to leave out the key frame data and apply a simple transformation myself to just one bone. 

This can be seen below: 

As you can see the arm rotates smoothly in a circle which proves that the Bone Hierarchy transformations are correct(at least for the bind pose). This points out that the issue is solely with how the key frame data is being loaded or that an extra transformation step needs to be done in order for the key frame data to be used. 

I'm definitely nearly there with this now, can't wait till its cracked.

Keep Coding :)

I've had another breakthrough with the animation and it now animates in a similar way to how it is supposed to look. There was some issues with the timing that caused the animation to jitter between only a few keyframes. Since getting this sorted and playing with a few of the transformations I have now got it pretty close, take a look: 

As you can see it is still quite a bit off, I definitely believe that this is now just an issue with the transformations and will hopefully get this figured out pretty soon. 

Just do what makes you happy :)

Still struggling with this animation problem, which is starting to set me back quite a lot. After trying every which order of transformation and looking online at a few different implementations I still can't figure out what is going wrong. 

My next step is to take it back to loading of the animation and see if I can see any problems with the matrices as they are being loaded. Luckily the model I'm using is stored in a human readable format so I can compare the data for the key frames easily.

The only other problem that I could see it being is an issue with the quaternions for the keyframes not being correct. This again can be tested by doing some debugging at the animation load time. 

Hopefully I will get there soon.

Keep Coding :)