Obtain a FireFox performance file by:

1. Make sure scene uses Babylon MAX.
2. Add the temporary Javascript line window.alert('Turn on Performance Recording') just prior to Engine Instancing line.
3. Load the scene, turn on performance profiling, & click ok to the temporary alert.
4. Do anything that might call code in babylon.js not yet encountered.
5. Stop recording, and save the data as a file.

On this page:

1. Select File with 'Browse' button below, and pick the file saved from above.
2. Make any changes of name to babylon file names & directory..
3. Click Generate. Tip: change Firefox Option for Downloads to Always ask me where to save files to avoid having to move custom config to Gulp Directory.
4. Copy the 'custom.cofig.json' file generated in Downloads directory to the Gulp directory.
5. Run: 'Gulp build-custom' then test with scene. Tip: test with the max version generated.
6. If need stuff did not get recorded in performance file, then select file(s) & click Generate again.

Firefox Chrome Edge
Profiling file:

Output Directory: (clear for default of ../../dist/preview release)
Filename: minFilename:
Files Not In Recording: (Select those to still keep)