[Bf-committers] Proposal for clarified VFX Reference Platform Support

Ray Molenkamp ray at lazydodo.com
Thu Jan 20 20:21:44 CET 2022

While I do not mind the practical nuts and bolts of this
proposal at all, I do mind the language, referring to the
VFX Platform as something worth looking at regarding file
or platform compatibility is unfortunate.

The Platform as is makes no attempt to manage file compatibility
throughout the pipeline, the big-ticket items in this space such
as USD and/or MaterialX aren't even in the platform, the things
that are in the platform, such as OpenVDB that have _severe_
file compat issues if build incorrectly do not even have a footnote
about it. The only logical conclusion here is, the VFX Platform
is a not authority to appeal to regarding file compatibility, so
best not to.

As for platform compatibility, the messaging in the VFX Platform
is confusing, for linux it declares a glibc version, for macOS it
declares a deployment target, so far so good, but then for windows
it does none of these things, and just recommends a compiler and SDK of
which neither determine the OS versions the resulting code can
run on, the inclusion of python 3.9 indirectly implies windows 8.1
is their minimum windows deployment target, but honestly I'm unsure
if even they are aware of this implication.

I'd like to see the proposal move more into concrete direction:

> Blender does NOT follow the VFX platform.
> - Blender aims be compatible with operating systems VFX Platform compatible software will be able run on.
> - blender aims not to break file compatibility for 3rd party formats such as EXR, VDB, Alembic: files exported from Blender should be usable in other software used in the pipeline, and vice-versa.

The last item

> - Not to break external render engines

Is just not something I think we can we can practically commit to,
these are generally linked directly to the python shared libs,
and bumping python versions will definitely break most if not all
of them.

To put an end to having to have this conversation every year, I'd
like to break the loop with the following text:

> Major blender releases will ship with the latest major python version available during BCON1 in its development.

My proposal

- Clarifies our stance on the VFX Platform
- Doesn't appeal to an authority the VFX Platform clearly lacks regarding file compat.
- Somewhat commits to running on the same platforms as the VFX platform (as much as it can be deduced from the platform, they are vague about it, hard to make any solid commitments here).
- Makes the python version blender will ship with predictable.

Note that personally, I may or may not approve of the direction being
taken here, but judging from your internal discussions this seems to be
the way we want to go as a project, in which case clear language is
undoubtedly better than vague commitments that sound nice but may
set unrealistic expectations.


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