DrawMeshInstancedIndirect & Soft-edge box rendering ?

Hello guys,

I'm quite new to shader.

Here is my question:

I used DrawMeshInstancedIndirect function and unlit surface shader to draw lots of boxes.

Then I used computerBuffer to change the alpha of each box.



However, I want those boxes rendered in a soft-edge or volumetric style.

What I researched so far is need to use the vertex shader to do ray tracing, but since I used GPU instancing, each vertex represents one box.

Any idea of how can I make it more soft-edge style, I basically just don't want it looks like tons of boxes.

Thanks