How to Mirror Animations in SFM!

A quick guide on something most people think is impossible:
Mirroring animations in SFM!!!

How to Mirror Animations in SFM!

Text guide coming soon™
TEXT GUIDE IS FINALLY HERE. IT ONLY TOOK 4 YEARS~!

This text version is a little more optimized. The order is just slightly different to be more efficient:

SECTION 1- MIRRORED PELVIS TRANSFORMATION SETUP
1. Make the first frame of the animation you want to mirror a T pose
2. Spawn a helper - Rename it to Original Path
3. Drag the pelvis onto the helper's root transform (parenting it)
4. Zero out the helper's root transform
5. Take the lock off the helper's root transform (unparenting it)
6. Zero out the helper's root transform's rotation

SECTION 2- MIRRORED MODEL SETUP
1. Make a copy of the model
2. Remove all animation data for the copy model (i.e. Just T pose)
3. Turn the original model upside down from the root (make sure it's still facing the same way forward) (make sure it's EXACTLY 180°)
4. Point constrain the pelvis of the original model to the pelvis of the copy model (MAKE SURE THIS IS DONE ON THE FIRST FRAME [T-POSE])

SECTION 3- MIRRORED PELVIS TRANSFORMATION
1. Make a copy of the Original Path helper - Rename it to Mirrored Path
2. Drag the pelvis of the copy model onto the Mirrored Path helper's root transform (parenting it)
3. Zero out the Mirrored Path helper's root transform
4. Take the lock off the Mirrored Path helper's root transform (unparenting it)
5. Zero out the Mirrored Path helper's root transform's rotation

SECTION 4- TRANSFORMATION CORRECTION & APPLICATION
1. Drag the Mirrored Path's root transform to the Original Path's root transform
2. Zero out the Mirrored Paths root transform's X & Y (not Z)
3. Remove the constraints on the copy model's pelvis
4. Drag the Original Path's root transform onto the copy model's pelvis (Yes, original. Not the mirrored. Sorry if that's confusing)
5. Drag out playhead (on the first frame [T-Pose]) on the pelvis.
6. Take the lock off of the copy model's pelvis
7. Delete both helpers

SECTION 5- MIRRORED MODEL ROTATION SETUP
1. Turn the original model around so that it's still upside down, but facing the other way (This will make L become R and vice versa) (MAKE SURE IT'S EXACTLY 180°)

SECTION 6- MIRRORED MODEL ROTATION
1a. For each bone, orient constraint the original model's bone to the corresponding copy model's bone [REMEMBER: ORIGINAL L TO COPY R | ORIGINAL R TO COPY L]
1b. Make sure you do this in the correct order (i.e. Pelvis to Spine to Head | Collar to Upper Arm to Lower Arm, etc.)

SECTION 7- FINALIZATION
1. Save your work
2. Right Click your Copy Model
3. Go to Constraints > Bake Constraints
4. Right Click your Copy Model
5. Go to Constraints > Remove Constraints
4. Delete all extra models

[A Metal Penguin]

If you remove the rig, the animation should stay. Though, the keyframes will be lost.
To keep the keyframes, copy the animation (ignore the warning) then paste. Turn the visibility on the original model off. In the pasted model, remove the rig, then follow this tutorial.

[King of gamers]

Do I have to remake the animation without the rig or can I make the animation then remove the rig?

[King of gamers]

Ok thanks

[A Metal Penguin]

No. Unfortunately you'll have to disable the rig

[King of gamers]

Does this work with rigs as well?

[A Metal Penguin]

@N!Tr0

Yes!

[Nitro]

Is it possible to just use this method but for posing a model?

[A Metal Penguin]

@NARbluebear I finally made a text guide. Why now after 4 years. IDK, I just felt inspired. Hope it helps! Please feel free to ask for clarification.

[A Metal Penguin]

It's not there by default. You have to select the very first frame and import the ref pose the same way you import throw_fire sequence. If you still have trouble, respond and I will help.

[NARbluebear]

I'm having a little bit of trouble with this. The animation I'm wanting to use (Scout's throw_fire sequence) never goes into the ref pose whenever I drag the green portion right while holding the alt key. Is there something I'm missing?