Viewport Render Animation breaks {serial} tag

[Alumx]

If you set Output to "//Output\test {serial}/" and render Viewport Animation, it'll fail to create a folder with appropriate number

Also Is it possible to auto-save viewport renders too?

[jeinselen]

Hey @Alumx!

Blender does not invoke the render_init and render_complete handlers when rendering the viewport. Short answer; from what I can tell, it's simply not possible to write a plugin that works natively with the render.opengl operator, only the render.render operator.

However, there may be some workarounds.

1. Custom script

If you manually sequence the existing plugin functions with a python call to the render.opengl operator, it should behave enough like the Blender handler system to work. Blender will freeze during the entire operation, just like when triggering a standard render from the Python API. You'd also need to set up a script for each of the three viewport rendering options (image, animation, and keyframes).

import bpy
import VF_autosaveRender

VF_autosaveRender.autosave_render_start(bpy.context.scene)
bpy.ops.render.opengl(animation=True)
VF_autosaveRender.autosave_render(bpy.context.scene)

2. Use Proxy Render

If you're only capturing camera viewpoints and just need a quick Workbench render shortcut, VF-BlenderProxyRender might do the trick. It uses the standard rendering system in Blender, but temporarily sets the engine to Workbench along with a few other settings, and works correctly with other plugins like VR_autosaveRender that depend on event handlers. As mentioned above, the Blender interface will freeze while rendering, but generally it's pretty fast (so long as your Workbench settings aren't crazy).

[jeinselen]

As of Blender 2.7.3, the autosave_render function has been renamed to autosave_render_end for better clarity.

Updated script to render a viewport image:

import bpy
import VF_autosaveRender

VF_autosaveRender.autosave_render_start(bpy.context.scene)
bpy.ops.render.opengl()
VF_autosaveRender.autosave_render_end(bpy.context.scene)

To render an animation: bpy.ops.render.opengl(animation=True)
To render keyframes: bpy.ops.render.opengl(animation=True, render_keyed_only=True)

Triggering a render from Python will freeze Blender as it waits for the operation to complete; the Python API is not thread-safe and I haven't found a way around this limitation.

[jeinselen]

Closing: Blender API limitation