Headless playblasts

Pipelines
1

Hi all,

I’m looking to run a playblast on a machine without graphics card or monitor, mainly involving Maya, but applies to any DCC with a GPU requirement.

The requirements are simple; produce the exact same result as cmds.playblast() but via the command-line, on a blind machine.

$ mayapy -c "from maya import standalone, cmds; \
   standalone.initialize(); \
   cmds.playblast(filename='/root/workspace/my_playblast')"

Worth noting, the above works well on a machine with graphics card and monitor. So all I need is some way of emulating the windowing system and GPU.

For usecase, think of dispatching playblasts of computationally heavy animations (300 frames, <30 seconds each) to a farm so as to save some of that local RAM and keep working.

I know this has been attempted and failed before, by greater developers than I, and I can see why. Playblasts are screengrabs of an OpenGL viewport and OpenGL runs on the GPU. No GPU == No viewport.

Mesa can solve that.

The next why is that playblasts are dependent on a window. Something to screengrab from. Even with offScreen=True(?)

Xvfb can solve that.

At this point I’m at a loss. The command successfully finishes, throws a few warnings, and produces a quicktime file with no content.

Full reproducible

Either install Maya and the list of dependencies from above or use the pre-built Docker image like.


$ docker run -ti --rm -v $(pwd):/root/workspace mottosso/maya
[root@343 ~]# mayapy -c "from maya import standalone, cmds; \
   standalone.initialize(); \
   cmds.playblast(filename='/root/workspace/myplayblast')"
[root@343 ~]# exit
$ hexdump -C my_playblast.mov
00000000  00 00 00 20 66 74 79 70  71 74 20 20 20 05 03 00  |... ftypqt   ...|
00000010  71 74 20 20 00 00 00 00  00 00 00 00 00 00 00 00  |qt  ............|
00000020
$
2

just off my head, if nothing else works - try sticking it into a VM. A VM usually has a GPU, even if the host is headless. GPU performance may be bad though but if you build something like a “playblast farm” it may be okay.

3

In my previous studio we’ve just used maya scanline renderer to generate “playblasts” on the renderfarm. We’ve disabled all the lights we’ve found in the animators scene, created a simple set of 3 directional lights with no shadows and rendered it. Worked like a charm, however this was very specific case because we’ve been only interested in seeing the poly meshes (you can’t render i.e. NURBS curves)