autostart animation (after an animated object is created
ZAxisUp
3DSMax generated animation (has Z axis pointing up), all original door OBANs seem to have this flag
<InitialTransform>
matrix4x3
Initial position transform matrix, last 3 values are X, Y, Z position values. X, Y, Z seem to be always 0 (or nearly 0) in door OBAN files. That would make sense because of their global use.
<BaseTransform>
matrix4x3
fixed transform matrix
<FrameLength>
int16
the value must be equal to the last
<FrameCount>
int16
fubared animation frame length (in 1/60 seconds); does not work
<HalfStopFrame>
int16
stop frame for the first "half" of the animation; used by door animations to distinguish between open and close sequences
<KeyFrames>
holds <OBANKeyFrame> tags
<Rotation>
quaternion
object rotation, can harvested from TRAM files
<Translation>
vector3
x y z object position
int32
elapsed time in frames, use short intervals for smooth animations
Transform matrices
Like all matrices in Oni, they are composed of 3 vectors defining rotation/scaling/shearing and a 4th vector defining a translation.
In the above table the 4 vectors are presented as rows (Direct 3D convention), although OpenGL and Oni use them as columns.
Affine transformations use a 4x4 matrix with 4 extra coefficients (in the presentation above, one would add one column on the right):
three projection transform coefficients (all of them are zero here); one final coefficient (always 1.0 for an affine transform matrix).
Alternatively, one can think of the 3x4 matrix as a 3x3 rotation/scaling matrix and a position vector
Let X=(x, y, z) be the position of a vertex in the M3GM
Let M=(m11, m21, m31; m12, m22, m32; m13, m23, m33) be the 3x3 matrix
Let R=(m14, m24, m34) be the translation vector
Then the absolute position of the vertex in the 3D world will be: X M + R
(left multiplication is used because of the row-major notation above)
Initial transform matrix
It is used to position the object in the environment before the animation is played.
When the animation is played, they use the fixed transform matrix and a quaternion.
Fixed transform matrix
This transformation is applied before the quaternion+position transform at every keyframe.
The only transform that can't be handled by the quaternion+position is scaling/mirroring.
Thus, the fixed transform is a scaling matrix most of the time (no rotation or translation).
On the hex page, the fixed transform scales the van up by 1.82 (along all three axes).
Quaternions
Those are used in Oni whenever interpolation of 3D rotation is involved (e.g., TRAM rotation)
In this case, rotation at intermediate frames is interpolated from the keyframe quaternions.
code sample
[...] means other code blocks of <OBANKeyFrame>...</OBANKeyFrame>
It's possible to create animations in Mod Tool and making TRAM files out of them. Then you can extract the quaternions and rotations with onisplit v0.9.54.0 and use them for OBANs.
HERE's an excel macro to harvest such data for camera animations.
wish list
TRAM import: dae + xml
the dae section in the xml file should have an option to create a pelvis OBAN along with the TRAM (see XML:TRAM, RealWorld flag for details)
dae to oni creation should also allow for OBANs (currently OBANs can only be imported via level master xml file)
this would be very useful for editing/creating single OBAN files if the rest of the level don't need changes
calculating a transform matrix step by step
In some scenarios we need to build a new transform matrix, e.g. when making a new weapon particle emitter.
Those commands can be used to examine OniSplit's matrix calculation.