XML:OBAN

The xml code on this page is compatible with onisplit v0.9.61.0 and v0.9.68.0

OBAN: Object Animation

general information

• OBAN files are level specific
• exception: OBANs of laser triggers are located in level0_Final
• trivia: also the dream lab images use OBANs
• tutorial: making camera interpolations

BSL support

animate object	animate character	animate camera
env_setanim object_id oban_name	chr_animate ai_name anim_name [num_frames] [interp_frames] chr_animate script_id anim_name [num_frames] [interp_frames]	cm_anim [look|move|both] oban_name
animate object (range)	stop animated character	interpolat between current and new camera position
env_anim object_id [object_id]	chr_envanim_stop ai_name chr_envanim_stop script_id	cm_interpolate oban_name frame_number

XML

tag	type	description
<Flags>	flag	NormalLoop BackToBackLoop RandomStartFrame Autostart autostart animation (after an animated object is created ZAxisUp 3DSMax generated animation (has Z axis pointing up)
<InitialTransform>	matrix4x3	initial position transform matrix
<BaseTransform>	matrix4x3	fixed transform matrix
<FrameLength>	int16	the value must be equal to the last value plus 1 because 0 is also a frame; Oni crashes if you use a wrong value for <FrameLength>
<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 intervalls 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>

<?xml version="1.0" encoding="utf-8"?>
<Oni>
   <OBAN id="0">
       <Flags></Flags>
       <InitialTransform>1 0 0 0 1 0 0 0 1 -225 9.3 -778.5</InitialTransform>
       <BaseTransform>-1 0 0 0 -1 0 0 0 1 0 0 0</BaseTransform>
       <FrameLength>80</FrameLength>
       <FrameCount>71</FrameCount>
       <HalfStopFrame>0</HalfStopFrame>
       <KeyFrames>
           <OBANKeyFrame>
               <Rotation>1 1 1 1</Rotation>
               <Translation>-225 9.3 -778.5</Translation>
               0
           </OBANKeyFrame>
           [...]
           <OBANKeyFrame>
               <Rotation>1 1 1 1</Rotation>
               <Translation>-217 34.5 -778.5</Translation>
               70
           </OBANKeyFrame>
       </KeyFrames>
   </OBAN>
</Oni>

data harvest from TRAM files

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.