I'm trying to learn how to do skeletal animation in Assimp and, as many people told me already, it's pretty harsh.

Until now I didn't really care about the order of the nodes and the respect to each node's parent. I just queried each node's mesh(es) and uploaded the required data (vertices, uvs, normals) to the GPU.

The result was looking good. I could even display models (that could also contain animations) in their bind pose without errors.

So, after attempting to learn skeletal animation I have a two questions:

1. Each node has a Matrix4x4 mTransformation member and I don't know why. Is it supposed to transform the vertices of the related meshes? Until now I didn't care about this data member at all.

2. Is there a good book that covers this subject widely? The (many) online tutorials I found are hard for me to understand.

From your description, it appears you're using only the transform for the node that "owns" a mesh.

What do you mean? I don't use the mTransformation matrix at all. How come I could display 3d models correctly until now if I haven't used it?

I render with OpenGL, btw.

I found this tutorial useful :

http://ogldev.atspace.co.uk/www/tutorial38/tutorial38.html

It shows how to render a skinned mesh from Assimp, using OpenGL.

Hope it helps

I found this tutorial useful :

http://ogldev.atspace.co.uk/www/tutorial38/tutorial38.html

It shows how to render a skinned mesh from Assimp, using OpenGL.

Hope it helps

Didn't find that tutorial useful because its code relies on a system that was built in previous tutorials. The explanations weren't so good either. (that's just my reflection)

I could even display models (that could also contain animations) in their bind pose

What do you mean? I don't use the mTransformation matrix at all. How come I could display 3d models correctly until now if I haven't used it?

You said yourself the models appear in "bind pose." If you're not using the local matrix for rendering the mesh then it's not in bind pose, unless the local transform happens to be an identity matrix. If the local transform for the mesh is an identity matrix, that's a result of the modeling technique, not your rendering application. In future, you may work with models for which the local matrices are not identity, and/or for which the local matrix must be multiplied by a to-root matrix to appear as expected. Rendering the mesh vertices without transformation may result in something that looks close to what you expect, but you're not displaying it "correctly" with regard to your programming routines.

That's weird. I did manage to render the next (pretty complex) 3d model without caring about mTransformation.

Anyway, I'm currently reading the tutorial you posted. I'll come back here if I have any questions.

I found this post had some useful information I couldn't find anywhere else: http://gamedev.stackexchange.com/questions/26382/i-cant-figure-out-how-to-animate-my-loaded-model-with-assimp/26442#26442

If you want to render him as he picks up his axe and lops off a head, you're going to have to start worrying about those bone transformations because that's how it's done.

I thought they were "node transformations" and not "bone transformation"..?

Also, as Buckeye stated:

Rendering the mesh vertices without transformation may result in something that looks close to what you expect, but you're not displaying it "correctly" with regard to your programming routines.

It seems that even without worrying about animations, not using the mTransformation data member produces incorrect (?) results, and I was just lucky that it displays the model correctly?