Control of blender settings via script

Question

Could someone please explain, line for line how this script works; in particular the dots in between the setting definitions s.proxy.build_50

import bpy

for s in bpy.context.scene.sequence_editor.sequences:
    if s.type != 'SOUND':
        s.use_proxy = True
        s.proxy.build_25 = True
        s.proxy.build_50 = False
        s.proxy.build_75 = False
        s.proxy.build_100 = False

I'm most interested in understanding how one finds out how to define other settings/switches.

I know you can right click on for online Python reference. Also hover over them to see a bit of code; but looking at these has just confused me.

Is there a list of other settings / code to define them?

CodeManX · Answer 1 · 2014-07-12T14:34:52.183

bpy.context.scene refers to the current scene, e.g. bpy.data.scenes["Scene"]

Sequence Editor data is stored in the Scene type, and .sequences contains the the top-level strips.

This iterates over all top-level sequences, whereas s refers to a sequence:

for s in bpy.context.scene.sequence_editor.sequences:

If the sequence is of type SOUND:

    if s.type != 'SOUND':

... the following code block is executed:

        s.use_proxy = True
        s.proxy.build_25 = True
        s.proxy.build_50 = False
        s.proxy.build_75 = False
        s.proxy.build_100 = False

A couple sequence properties are set.

Other sequence types:

>>> [item.identifier for item in bpy.types.Sequence.bl_rna.properties['type'].enum_items]

['IMAGE', 'META', 'SCENE', 'MOVIE', 'MOVIECLIP', 'MASK', 'SOUND', 'CROSS', 'ADD', 'SUBTRACT', 'ALPHA_OVER', 'ALPHA_UNDER', 'GAMMA_CROSS', 'MULTIPLY', 'OVER_DROP', 'WIPE', 'GLOW', 'TRANSFORM', 'COLOR', 'SPEED', 'MULTICAM', 'ADJUSTMENT']

You can pick a single sequence and get the type:

>>> type(bpy.context.scene.sequence_editor.sequences[0])
<class 'bpy.types.SceneSequence'>

Check the API docs to find out about the properties and methods: bpy.types.SceneSequence

.proxy is a subtype, which has several own properties: bpy.types.SequenceProxy

Don't miss to read this:

Blender/Python API Reference Usage: examples of how to use the API reference docs

score 2 · Accepted Answer · edited Apr 13 '17 at 12:57

bpy.context.scene.sequence_editor.sequences is a list like:

list = ["a", "b", "c"]
for element in list:
    print( element )

this would print:

a
b
c

the for loop assigns each element from the list to a variable executes the commands (print in this case) and advances to the next element.

The same applies to your snippet s gets on value after another from the defined sequences. Adding a print statement before the if statement would show something like that:

<bpy_struct, ImageSequence("main_chart.jpg")>
<bpy_struct, ImageSequence("main_chart.jpg")>
<bpy_struct, SoundSequence("sound.wav")>

Now you know the name of the classes (ImageSequence or whatever is printed) and you can lookup the API Documentation

The dot is a syntax element that separates the name of an object by its properties.

You could also examine the available properties by using dir

print( dir(s) )

Which would print for an ImageSequence:

['__doc__', '__module__', '__slots__', 'alpha_mode', 'animation_offset_end', 
'animation_offset_start', 'bl_rna', 'blend_alpha', 'blend_type', 'channel', 
'color_multiply', 'color_saturation', 'colorspace_settings', 'crop', 'directory', 'effect_fader', 'elements', 'frame_duration', 'frame_final_duration', 
'frame_final_end', 'frame_final_start', 'frame_offset_end', 'frame_offset_start', 'frame_start', 'frame_still_end', 'frame_still_start', 'lock', 'modifiers', 'mute', 'name', 'proxy', 'rna_type', 'select', 'select_left_handle', 'select_right_handle', 
'speed_factor', 'strip_elem_from_frame', 'strobe', 'swap', 'transform', 'type', 
'update', 'use_crop', 'use_default_fade', 'use_deinterlace', 'use_flip_x', 
'use_flip_y', 'use_float', 'use_linear_modifiers', 'use_proxy', 'use_proxy_custom_directory', 'use_proxy_custom_file', 'use_reverse_frames', 'use_translation']

Control of blender settings via script

2 Answers2