Source 2 stereo controllers are not functioning, if created with the engine.
Since I was unable to register to the Dota 2 dev forums (because it requires dota 2 beta(?) which is no longer obtainable), I had to post the issue about the Source 2 Filmmaker stereo controllers (faceflexes).

Please let me know if I have to post this to a different section, but according to the FAQ, this is also the place to post Source 2 Filmmaker bugs(?).

The problem:
Source 2 breaks the _left stereo controllers if they were compiled/created via the engine itself.
Illustration with a GIFV, I can post other formats if required.[i.imgur.com]

Included example files and description:
Google drive link // Let me know if I should upload this to Dropbox or other alternatives instead.

I included the following folders:

source-1-filmmaker-working-example // An example of a working Source 1 model, in Source 2 however is slightly off, because the _left stereo controller is not working.

files-dota2-example // Has 2 folders, both working and not working examples in Source 2. ( The working example is too complicated to setup in any 3D editing tool with corrective flexes )

files-dota2-saxton // An example of a complicated (hwm) head, works in Source 1, but the _left flexes do not work in Source 2 as stated in the issue itself.

The Dota 2 examples:
Note: The starting shape is a sphere

How it looks in Source 1: (note, just from InnerSquint and BrowOutV, it automatically created left_ and right_ based on $stereo 1 in flex controllers)
https://i.imgur.com/Ie2VczM.png


How it gets seperated to L and R automatically in Source 1. (This is a weight group, later examples shows how the "DMX Stereo Balance" is recognised by both Source 1 and Source 2)
https://i.imgur.com/SpBFW3K.png

How it looks in Source 2: (Exactly the same files used but in Source 2, however the _left side is ignored, note: the Morph explorer values, also the engine uses the "DMX Stereo Balance" Vertex group to create the working _right side)
https://i.imgur.com/NrzROpx.png

Example files description:

test_stereo_s1fm_method:

An example that works in Source 1, and is ALMOST working in Source 2, but the _left side does not react to the controller. (Note: Controller source has $stereo "1" that automatically creates the _left and _right based on the "DMX Stereo Balance" weight group)

GIFV to demonstrate how it works in Source 2: https://i.imgur.com/0rCe9gZ.gifv // On the serious note, if this could be fixed, we would be able to progress.

GIFV to demonstrate how it works in Source 1: https://i.imgur.com/XBVSUxk.gifv //

test_stereo_working_method:

This is a working example, but is unneccesarily complicated (most specificly, with corrective flexes, makes it exponentionally harder to create with most 3D editing softwares, creating _left and _right side manually is tedious). The goal of the Source 1 method is to create these _left and _right sides automatically, saving all the neccesary work to focus on iteration of corrective shapes.

On a side note, here are other issues with the source 2 morph system:

- Wrinklemap support is not integrated with materials(?). Any documentation / implementations of that would be welcoming.

- Domination rules are not functioning, in Source 1 It was a feature that allowed specific flex combinations to be suppressed, avoiding specific combinations without correctives (e.g using OpenJaw and PuffLips is not possible, domination rules ignores the PuffLips when OpenJaw is used)

Since the Dota 2 film contest has started, we would like the developer team to address some of these issues, preferably the Stereo controller issue, as it seems to be a minor one.