Thanks for the replies. Sounds like I have several options.
wdcrvr
If you build laser cut wood kits, save all the bits and pieces and nubbins. There would be good fodder there for filling in for a missing pane of glass or two (and other projects).
I have used actual glass slide cover slips as the glass in some windows, and I have also broken some of them to model broken windows. Of course since it is real glass and is really broken it has a sharp edge so be careful.
Dave Nelson
When I have large multi-paned windows like this...
I use canopy cement for the glazing. This fills the openings with a clear plastic when it hardens, and also distorts any light trying to pass through so you can't see that the building has no interior. You can't really see them, but I used small pieces of wood coffee stirrers to replace some of the "window glass."
This is from the Weimer's Mill kit by Branchline:
I used the same thin glazing plastic and just cut off a couple of corners.
It takes an iron man to play with a toy iron horse.
If individual panes are replaced with wood, the wood is usually cut to fit and placed where the glass was. If there's a window with many panes, some of which are broken, sometimes a sheet of plywood is placed covering the whole thing. I would think inside or outside would "depend".
You don't have to use a "very thin piece of styrene" unless you can see the inside. If you've got tilt-open windows, that might be the case.
Another possibility is to print the wood filler with an ink jet printer. Cut out and install. If it's too curvy, glue it onto that styrene.
Ed
I am assembling the Walthers Diamond Coal Mine. I have managed to trim some of the smaller multi-paned windows so that I can install them in a tilted open position. (Unfortunately I didn't think of that until I had already glued them all in and had to go back and see how many I could persuade to come back out.) Now I would like to indicate that some panes of the windows have been broken out and replaced with a piece of wood. I am having some trouble trying to envision how they would look. I am guessing the wood would be set in the frame the same as the glass pane? Would it look reasonable to fill a pane with a very thin piece of styrene and then paint the outside surface to look like bare wood or painted wood? I will appreciate any and all ideas. And if anyone has pictures, that would be great.
Thanks