I hear you. Manufacturer stuff will still have to be separated by folders, but the $CONTENT-DIR$ variable should still allow for a single preset.
I am still learning about the variables myself. The world as we know it will never be the same. 
I may go back into my presets and change the regular MAME and ARCADE to use the variables. But I’m not sure how much help this will be to users making custom variations. I would need to look at some sample custom presets.
Well, I placed the .param files, added the reference in my default preset and changed my game path in LB back to my main roms folder, and it launched the first game I tried in vertical orientation. Pretty impressive.
So, my next question is… if I have a different default vertical and horizontal bezel (I do), how do I make it use the correct one?
edit Could I have it direct the core orientation to my old default vertical file, which includes the scale and my vertical default bezel?
edit It looks like you can’t have reference lines in the .params? Mine keep failing to load the shader.
Yep. You just need the parameters. You should have the only base reference in the main file.
You are on the right track, it just takes practice.
You can reference slangp files in the params but it would not be recommended. Only one slangp file can be referenced in the chain of params and base slangp.
So, if I am not referencing anything in the .param files, how can I get it to select the proper background image between my default vertical and default horizontal?
To make things abundantly clear (Because language can cause confusion.) You can have as many references as you like/need in a preset (A reference chain.) but only one reference can point to a file that contains a shader chain.
For an of example removing a shader chain from a standalone Guest preset to create a params file, you can read my “Params_02_Community_Derived_Params.md”.
It should make things a bit clearer.
You can have image paths, just not a reference to a base preset.
In your case it may be easier to use my legacy presets so all the info you need can be in two params files.
The guide I mentioned above also details how to flatten my current presets if you need.
You should be able to use my The Bezel Project slangp and just rename your layers by adding $GAME$_ at the beginning of the image path names. Then rename your images to match the game. e.g. mspacman_glass.png.
Again… I would need to examine your presets to give exact advice.
So, MAME.slangp > MAME$Core_Aspect_Orient$ > My Default Vert or Horiz.slangp is possible? Because I am getting repeated failure to load. I keep checking my syntax but everything seems right.
I recommend using the params extension to avoid confusion. I’ll need to see a log but make sure your params files are named “CORE-ASPECT-ORIENT-VERT.params” etc. (The variable can be just part of the filename also. Take a look at my filename usage in the The Bezel Project example.
Wait… I think I just got it working. I had to use the "#reference “:/” instead of the #reference "…/…/…/ that I used to use for the same folder. Is that a new thing?
Regardless, I just got it to load with my default vertical setup for a vertical game in my default roms folder. 
Depends on where you params file are in relation to your slangp. If they are in the same folder then no leading paths are needed.
Now you just need to test a horizontal game using the same preset.
BTW. I always keep a debug level log window opening with RA to make finding these errors easier.
Yes, they are in the same folder with the .slangp that they point to. Counting the folders …/ to the RA folder would fail every time.
Yep. Again, look at my The Bezel Project slangp.
Glad you got it working. There is always a learning curve. @HyperspaceMadness changed the variable names many times during development so I got in a little more practice.
Horizontal games are a check 
So, I am officially running vert and horiz default presets with all arcade roms in the same folder, which is great. I also learned several new things today. Thank you!
You are welcome!
Now… if you are planning on doing Manufacturer presets, and have your games separated into manufacturer folders. You can add the$CONTENT-DIR$ variable to the name of your images.
Assuming a “MAME” roms folder name for your normal roms and “Atari” as one of the manufacturers…
“$CONTENT-DIR$_glass.png” would resolve to “MAME_glass.png” or “Atari_glass.png”.
Then you would still only need the single core preset to load everything.
I’m thinking I may rename all my bezels with MAME naming convention so that I can take advantage of that feature. That may be a project for another day.
Manufacturers, I’m not sure. I might like to do a raster/vector if that is possible.
Yeah, I was actually making that post for the general public to read. Thanks for the opportunity. 
You are talking about renaming your bezel art PNGs though…correct?
If you separate your vector games to a “Vector” folder in will work like I said, but you will also need to add the name of your raster roms folder to your images.
@HyperspaceMadness has a link on his thread to his GitHub commit with wildcard info. For the sake of convenience I have also added a Wildcards.md to my guides folder, with the same info.
Drybonz, definitely do this if you are working with the wildcards, if it fails to find the wildvard option it’s looking for it will print out what it was looking for which should help identifying path issues
It would be really cool if you could include these Arcade bezel variations that are derived from your work by @soqueroeu:
The FBNeo version looks much better than your default one IMO.
There’s also this cool portrait variation:
