I’m really struggling with getting my Collada model to animate correctly, and it’s turning into quite the nightmare. So, I’m working with a model that I pulled from a Collada file, and my main issue is that the vertices end up looking like this bizarre shapeless goo reminiscent of something from the movie “The Thing.” Not exactly what I had in mind!
I’ve been following a tutorial on the ThinMatrix YouTube channel, which seemed straightforward enough. But as it turns out, getting this animation to work properly is a whole different story. I’ve started by checking the Quaternions class, thinking that might be the root of the problem—whether it’s during their creation from matrices or when I try to convert them back into rotation matrices.
I’ve tried multiple approaches and experimented with quite a few transformation matrices. First off, I made sure to transpose all the matrices that I’m pulling from the Collada file. I double-checked the indices for the animation transformation matrices that get passed over to the Shader. I even dived into the world of Inverse Bind Matrices, swapping in both the controller skin’s provided matrix and my own custom creations.
Ah, and here’s where it gets even trickier: I adjusted the order of multiplication for the animation matrices. I tried everything from `vertex * bindShapeMatrix * TransformMatrix * InvBindMatrix` to multiplying just with the parent matrices and even moving all the way up to the root joint. Despite all of this, nothing seems to be working!
I’ve stashed the vertex data in a file called “body.txt,” and you can check out the whole project on my GitHub repository [here](https://github.com/edilon-junior/OpenglEsAnimation). The model itself is located in the path `Assets/human/human.dae`.
If anyone has run into this issue or has any insights on what might be going wrong, I would greatly appreciate your help. I’m starting to feel a bit lost here, and every tweak I make seems to lead to more colorful chaos rather than the smooth animation I was hoping for!
Wow, it sounds like you’re really deep into a tricky problem with your Collada model! It can be super frustrating when everything you try just seems to make things worse. I totally get that feeling of spinning your wheels, especially with animations where one little hiccup can cause chaos.
It seems like you’ve done a lot of troubleshooting already! Checking the Quaternions class and the transformation matrices is definitely a good start. It’s a classic issue with 3D models; sometimes, the math just doesn’t behave the way you expect it to. The fact that you’re checking the indices for the animation transformation matrices is a smart move since any mismatch can lead to those ‘gooey’ vertex problems.
One thing to consider is the assembling of your transformation matrices. If the order of your matrix multiplications doesn’t match the expected hierarchy for the animation, it can lead to that wonky shape. You mentioned trying different orders, but sometimes even a minor adjustment can make a significant difference!
Also, have you double-checked the vertex weights for skinned meshes? Those weights can drastically change how vertices react to skeleton transformations. If they’re really off, it could lead to bizarre deformation.
And about the Inverse Bind Matrices: make sure they’re correctly applied in the skinning process. If they’re not in the right place, that can throw everything off. Maybe take a step back and confirm that everything matches up with how your model is structured in the Collada file.
It looks like you’re already sharing your project on GitHub, which is awesome! If you haven’t done so yet, it could be helpful to get some eyes on your code and model. Sometimes fresh perspectives can catch something you might have overlooked.
Hang in there! Debugging these things can be a bear, but you seem to be on the right track. Good luck with your project! I hope you can turn that goo back into a smooth animation soon!
It sounds like the issue you’re encountering typically stems from the order and format of matrix transformations, particularly related to bones and skeletal animations in Collada files. Firstly, verify that your inverse bind matrices extracted from the Collada file exactly match the file’s defined matrices without additional transformations, as even subtle differences can distort animations. Pay close attention to the column-major or row-major ordering of matrices; discrepancies here often result in the strange distortions you’re seeing. Additionally, reviewing your quaternion implementation thoroughly—especially conversions between matrices and quaternions—could reveal issues causing unexpected vertex deformations.
Since you’ve already tried various transformations, I recommend simplifying your animation pipeline step-by-step. Start by testing a single joint with a minimal rotation or translation, observing its isolated effect to pinpoint precisely where distortion occurs. Utilize debug visualizations or simpler test models (with fewer bones and simpler bone hierarchy) to help isolate potential causes. Tools such as Blender or other dedicated Collada viewers can also help to verify if the exported model and animations are correct. Carefully ensuring consistency in matrix multiplication order (usually vertex multiplied by bind shape, joint transforms, and then inverse bind matrices) will help narrow down or debug your issue more effectively.