How do I get the material's base color alpha work as transparency in the shader? How do I get the Principled BSDF shader to display the base color alpha as transparency or without using nodes?

Most of the questions seek to interpret the alpha channel of an image texture as transparent, but my context is simpler: the Base Color of the Material has 0.3 alpha.

Yet, the object is not transparent in either the editor, the render (cycles or evee), but it is actually exported in collada.

Without success, I have tried:


Setting the base color alpha -> does carry out to a collada export, but is not transparent in the editor
Changing the Blend Mode -> does not carry out to a collada export
Changing the viewport display -> only displays as transparent in solid mode


Using nodes I've tried


Setting the transmission value -> doesn't do anything
Changing to Glossy or Glass -> doesn't carry out to collada


I think that's all I tried. I did get it to work in the render, but I do need it to carry out to a collada export.



The transparency of the base color is ignored in the rendering and the editor. Is there a way to display it in the render or the editor like Blender displays the viewport display alpha?
Base color value can be used as a driver of transparency. It is depending on shader if it can read and interpret that information. Principled shader is one which can. Diffuse shader won't be able to do it without mixing it with Transparent shader and driving Mix shader factor.

If you open color picker of Principled BSDF and set its alpha to 0 and color to white                  you will get only white material because shader renders it as basic diffuse surface by default.  

If you set Transmission value of the shader to 1 allowing it to happen shader will use alpha channel and will make your material as allowing light to come through it.  

However at this point it will refract light because by default shader's IOR value is set to 1.45 (common case of usage for interface between air and glass). Set that to 1.00 so no refraction happens and light comes straight.



Roughness value can be also taken down to 0 so it doesn't try to create rough surface. Object will still cast shadow of course; you will need to add more complex node setup or to disable shadow in material setitngs.