How to set alpha for all objects?

Question

blender newb here. I've exported a .dae from Revit using the lumion plugin in Revit and I'm trying to follow this tutorial.

My issue is that when I import the .dae to blender. Everything shows up black.

In the comments, someone has suggested checking the alpha channels to see if they are all set to 0...which I find to be my case. They then suggest changing all the alpha channels from 0 to anything above.

Here is the alpha setting I am referring to:

I am finding myself having to go through each blender object and setting the alpha one by one. Is there a faster way to do this besides scripting? also, I have no idea what the alpha setting is for so any insight on that would be appreciated.

I've tried selecting multiple objects and changing but it only changes the last one I selected. I've also tried mouse drag over all and set it but it's still the same result.

Here is what my scene looks like. The black objects have the 0 alpha

Any help/direction is appreciated.

Answer 1

I'm not aware of one besides scripting. Here is a script that should do it:

import bpy

for mat in bpy.data.materials:
    if not mat.node_tree: continue
    for node in mat.node_tree.nodes:
        if node.type == 'BSDF_PRINCIPLED':
            soc = node.inputs["Alpha"]
            if soc.is_linked or soc.default_value > 0.01:
                continue
            soc.default_value = 1.0

Alpha is a transparency value: 1.0 is opaque and 0.0 is completely transparent. However in Eevee for it to work you must also set the material's "Blend Mode".

Answer 2

If you want to set a parameter for a bunch of selected objects through UI (if they share a same kind of property) just enter the value and while holding Alt press Enter, or hold Alt and drag the value to set it for all of them

Edit

Although it works for any property that share a same address this doesn't work for material properties and it's weird!