Baking smoke on headless machine

Question

I have a linux vps that has some spare resources left from main activity. I can not get the GUI working, but I was thinking if there is a way to use it for baking with python script.

I see that there is an operator:

bpy.ops.ptcache.bake(bake=True) 

But what is the right context for it?

Also if anyone has ideas to get the GUI working under Ubuntu VPS, that would be much appreciated.

Answer 1

Baking smoke is very similar to baking fluid, so I will quote brecht's answer:

It's a bit more complicated than it could be because fluid simulating baking is only exposed as an operator. That means it expects an active object in the context, which is usually provided by the user interface that is not available in background mode.

However, it is possible to override context manually, see this answer as well as the documentation.

For a smoke simulation, this might look like:

import bpy

for scene in bpy.data.scenes:
    for obj in scene.objects:
        for modifier in obj.modifiers:
            if modifier.type == 'FLUID' and modifier.fluid_type == 'DOMAIN':
                if modifier.domain_settings.domain_type == 'GAS':
                    with bpy.context.temp_override(scene=scene, active_object=obj):
                        # bpy.ops.fluid.free_all() # if you'd like to free existing bakes first
                        bpy.ops.fluid.bake_data()

^{updated for blender 3.4+. for pre-mantaflow version (<2.82) see this revision}

This will bake the selected cache for all domain objects in the file.

You can then run this python script in blender with

blender --background /path/to/file.blend --python /path/to/script.py

Or the short way:

blender -b /path/to/file.blend -P /path/to/script.py