Hi, When modeling I usually create a material called working which is a dark grey material that has animated opacity so that I can see the references better. After I did like 70% of a model I put on a wip material close to the colors that what I am modeling should be. Sometimes I would like to make changes instantly…
You can always animate your materials to your needs. Then set the active animation range to 0-1. With the Home and End keys you can switch back and forth.
Just so I'm clear, are you wanting to keep you WIP/colour material, but make the mesh partially transparent? If that is the case, there's 3 methods I can think of that could work. You can manually edit the opacity by selecting the object mesh - right click - object properties - General Tab. The non the lower right there is…