Adjust posture in retargeted animations. #147
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This was referenced Dec 25, 2023
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Several models across the main HL games have custom sequences (both in LD/HD) but some have different bone hierarchy (armature), which required retargeting animations between each incompatible armature.
A tool was created to allow automating the process in converting each required animation. This also allowed to make animations more reusable across various models and add animations that were previously only restricted to specific models.
https://github.com/malortie/smd-tools/blob/master/test_smd_tool
The tool follows a pipeline like architecture. It loads SMDs and applies a set of operations based on the need of each case. In most of the cases, an operation was used to resolve feet positions so they could be positioned at the center between the two feet position in the original animation. There is no support for IK, which is the main concern in this issue.
The animations were converted so that they would try to rotate the same way as the input armature but since the two armatures don't necessarily have the same bone lengths for the arms or spines, the arms may not always end up close enough to the locations they are intended to be.
Whether or not it's an issue depends on the context of each animation. If the character doesn't need to hold an object and or extend an arm to a specific location, there's no need to adjust anything.
Each converted sequence was at first reviewed and deemed 'OK' but there are a few identified situations where this could be improved:
Scientist:
crowbar_swingdrive_jeep1,drive_jeep2tap_down,tap_idlewallworksequencesWays to approach this situation:
A)
Implementing IK in the tool would be complex and does not guarantee to give adequate results. Remember that if both armatures don't have the same bone lengths, you can't just stretch the bones since it'll make the animation look glitchy. The only way is to run multiple simulations using combination of rotations for all the bones (possibly starting from the pelvis) that work concordantly with the target arm(s) and hope for an adequate result. Remember that this needs to blend across all frames of the animation for which the position of the arm(s) is important. This may potentially require a lot of trials/errors. Note that this approach does not allow easier further editing of the animation since it depends on an arbitrary process rather than using a 3D scene file.
B)
Manually fixing the animation at specific frames is highly probable to be less time costly than the above. In cases of sequences where the character is standing still or arms aren't moving too often (e.g.
tap_downandtap_idle) then making small rotations would probably be sufficient but in cases of more complex animations, a rig with IK will likely be required.Characters rigged to use IK are usually animated using controllers provided by the rig developer. The ideal solution would be to have a rig whose controllers have the same orientation as the target HL skeleton bones. This would allow to simply copy each bone transform to their associated controller and rebuild the animation on top of the controllers. Once you have all transforms, you could technically use the Decimate Keyframe feature to remove unneeded keyframes (simplify animation curves) and only correct the position of the arm(s) at specific times. If the IK rig does not match the bones transforms, then manually moving each controller to their respective bone will be required for each frame of the animation.
It may also be interesting to have an IK rig for animators to use to create custom animations more easily.
Solution B) is recommended.
Below is a list of all converted sequences.
Note: Most of the sequences listed below are shared between models, so the actual number of sequences is actually much lower.
Scientists
LD scientist
Ported from Blue Shift LD scientists sequences:
Ported from Blue Shift LD civilian scientists sequences:
Ported from Blue Shift LD civilian newspaper scientists sequences:
Ported from Blue Shift LD console civilian scientists sequences:
Ported from Blue Shift LD
scientist_cower.mdlsequences:Ported from Blue Shift LD Gordon scientist sequences:
HD scientist
Ported from HL1 LD scientists sequences:
Ported from Op4 LD scientists sequences:
Ported from Op4 LD cleansuit scientists sequences:
Ported from Blue Shift HD civilian scientists sequences:
Ported from Blue Shift HD civilian coat scientists sequences:
Ported from Blue Shift HD civilian newspaper scientists sequences:
Ported from Blue Shift HD console civilian scientists sequences:
Gman
LD Gman
Otis
LD Otis
Ported from Blue Shift LD Otis sequences:
Ported from Blue Shift LD
intro_otis.mdlsequences:Barney
HD Barney
Ported from Op4 LD Otis sequences:
Ported from Blue Shift LD Otis sequences:
HGrunt
LD HGrunt
Ported from Blue Shift LD HGrunt sequences:
Ported from Op4 LD Massn sequences:
HD HGrunt
Ported from HL1 LD HGrunt sequences:
Ported from Op4 LD Massn sequences:
Skeleton
LD Skeleton
Massn
LD Massn
Ported from HL1 LD HGrunt sequences:
Ported from Op4 LD friendly grunts sequences:
Ported from Op4 LD
intro_commander.mdlsequences:Ported from Op4 LD
intro_medic.mdlsequences:Ported from Op4 LD
intro_regular.mdlsequences:Ported from Op4 LD
intro_saw.mdlsequences:Ported from Op4 LD
intro_torch.mdlsequences:HD Massn
Ported from Op4 LD
intro_medic.mdlsequences:Ported from Op4 HD
intro_regular.mdlsequences:Ported from Op4 HD
intro_saw.mdlsequences:Ported from Op4 LD
intro_torch.mdlsequences:Ported from Op4 HD friendly grunts sequences:
Op4 friendly grunts
LD Op4 Medic
LD Op4 Engineer
LD Op4 grunts (hgrunt_medic.mdl, hgrunt_opfor.mdl, hgrunt_torch.mdl)
HD Op4 grunts (hgrunt_medic.mdl, hgrunt_opfor.mdl, hgrunt_torch.mdl)
Op4 Intro grunts
LD Intro Regular Op4 grunt (intro_regular.mdl)
LD Intro SAW Op4 grunt (intro_saw.mdl)
HD Intro SAW Op4 grunt (intro_saw.mdl)
LD Intro Torch Op4 grunt (intro_torch.mdl)
LD Intro Medic Op4 grunt (intro_medic.mdl)
Zombies
LD Zombie scientist
Ported from Op4 LD zombie soldier sequences:
HD Zombie scientist
Ported from Op4 LD zombie soldier sequences:
Ported from HL1 LD zombie scientist sequences:
LD Zombie soldier
Ported from HL1 LD zombie scientist sequences:
Ported from Blue Shift LD zombie scientist sequences:
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