Okay, I think I see what you mean though something still does not quite add up (thanks for your patience here).
If I select front/back face colors (in the Style window under the Edit heading), the boxes reflect the colors that I chose. They also reflect the opacity that I chose. Then if I make some faces, they have the color indicated in the boxes (the ones I chose), but their opacity is 100% no matter what. I’d like them to be filled in with BOTH the color and the opacity that I picked.
If I then change the front/back colors in the Styles window all the faces I drew change color (as you explained). I’d rather they didn’t. I’m okay with defining a new color, or whatever is entailed, to get faces to fill as desired as I make them.
Let me give a hypothetical situation. What I’m actually doing is making a mathematical model to use at some conference talks, which is probably why my requests are weird, (since this program is more for architecture and stuff) so let me make up a different example that may relate my point.
Let’s say I’m making a 100 story building where everything in it, even the floors and ceilings are made of glass, and the color and opacity of the glass varies. Let’s say I want to represent each plane of glass with a flat face (with no thickness). For simplicity’s sake, let’s say I want each side of the building a constant color but different from the other sides (BUT each side made up of many many faces with edges in between). And let’s say I want everything inside the building to be white at 50% opacity on both sides.
This would give a cool effect where objects in the building have ghostly looks and fade off into the distance as you look through a wall. (This is similar to the kind of effect I want in my math models.)
So far, the only way I have of doing this is to make my structure, then manually select each group of faces that will have common color/opacity settings, and adjust them using Entity Info. That means I have to pick every single little face on the side manually. And doing the interior is a nightmare.
Clearly it would be way better to set the color/opacity first, make all the faces with that setting, then change it and make the next group, etc. Would you be kind enough to walk me through some way of doing that? Or, just let me know for sure if that is definitely impossible in Sketchup?