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@@ -397,9 +397,9 @@ void ConvertMaterial( aiMaterial* matIn, D3DMATERIAL9* matOut )
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@section bones Bones
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-A mesh may have a set of bones. Bones are a means to deform a mesh according to the movement of
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-a skeleton. Each bone has a name and a set of vertices on which it has influence. Its offset matrix
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-declares the transformation needed to transform from mesh space to the local space of this bone.
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+A mesh may have a set of bones in the form of aiBone structures.. Bones are a means to deform a mesh
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+according to the movement of a skeleton. Each bone has a name and a set of vertices on which it has influence.
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+Its offset matrix declares the transformation needed to transform from mesh space to the local space of this bone.
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Using the bones name you can find the corresponding node in the node hierarchy. This node in relation
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to the other bones' nodes defines the skeleton of the mesh. Unfortunately there might also be
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@@ -415,7 +415,7 @@ b2) Mark this node as "yes" in the necessityMap. <br>
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b3) Mark all of its parents the same way until you 1) find the mesh's node or 2) the parent of the mesh's node. <br>
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c) Recursively iterate over the node hierarchy <br>
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c1) If the node is marked as necessary, copy it into the skeleton and check its children <br>
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-c2) If the node is market as not necessary, skip it and do not iterate over its children. <br>
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+c2) If the node is marked as not necessary, skip it and do not iterate over its children. <br>
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Reasons: you need all the parent nodes to keep the transformation chain intact. Depending on the
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file format and the modelling package the node hierarchy of the skeleton is either a child
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@@ -428,6 +428,37 @@ You should now have a mesh in your engine with a skeleton that is a subset of th
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@section anims Animations
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+An imported scene may contain zero to x aiAnimation entries. An animation in this context is a set
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+of keyframe sequences where each sequence describes the orientation of a single node in the hierarchy
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+over a limited time span. Animations of this kind are usually used to animate the skeleton of
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+a skinned mesh, but there are other uses as well.
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+
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+An aiAnimation has a duration. The duration as well as all time stamps are given in ticks. To get
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+the correct timing, all time stamp thus have to be divided by aiAnimation::mTicksPerSecond. Beware,
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+though, that certain combinations of file format and exporter don't always store this information
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+in the exported file. In this case, mTicksPerSecond is set to 0 to indicate the lack of knowledge.
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+
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+The aiAnimation consists of a series of aiBoneAnims. Each bone animation affects a single node in
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+the node hierarchy only, the name specifying which node is affected. For this node the structure
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+stores three separate key sequences: a vector key sequence for the position, a quaternion key sequence
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+for the rotation and another vector key sequence for the scaling. All 3d data is local to the
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+coordinate space of the node's parent, that means in the same space as the node's transformation matrix.
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+There might be cases where animation tracks refer to a non-existent node by their name, but this
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+should not be the case in your every-day data.
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+
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+To apply such an animation you need to identify the animation tracks that refer to actual bones
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+in your mesh. Then for every track: <br>
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+a) Find the keys that lay right before the current anim time. <br>
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+b) Optional: interpolate between these and the following keys. <br>
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+c) Combine the calculated position, rotation and scaling to a tranformation matrix <br>
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+d) Set the affected node's transformation to the calculated matrix. <br>
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+
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+If you need hints on how to convert to or from quaternions, have a look at the
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+<a href="http://www.j3d.org/matrix_faq/matrfaq_latest.html">Matrix&Quaternion FAQ</a>. I suggest
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+using logarithmic interpolation for the scaling keys if you happen to need them - usually you don't
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+need them at all.
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+
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+
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@section textures Textures
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*/
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ulfjorensen