Grade: A - Enchanted Edition Grade: D - Regular Edition
If you have the newer Enchanted Edition of Trine, there should be a menu option to disable the hud.
If you're using the Regular Edition, there are two methods of disabling the hud, one temporary (good for screenshots, but not playing). The second method is permanent, so you better really not want the hud because it involves editing game resources.
To disable the hud, press F8. Then type hideGUI. You can't move unless you also run the command: enableControls. If you want to disable the character, type hideAllUnits. That lets you take nice screenshots of just the scenery, but it also disables some world objects (like platforms). The problem with doing this method is that it disables the crosshair, which really makes the game hard to play.
To disable the hud permanently, but keep the crosshairs, Go to the directory: Trine\dev
copy the cache.fbz file
rename the original file cache.zip
open the file.
go to the directory data/gui/hud/ingame
delete all of the .fbi files (which are really .dds files) in the data/gui/hud/ingame directory inside the cache.zip file. Or, just delete the "ingame" folder completely.
Exit the zip file
Rename it back to cache.fbz
Start the game and the hud will be gone.
You can delete the files from the other directories in the data/gui/hud folder if you wish. The ones suggested get rid of the parts of the hud that are always displayed, but keep notifications and parts of the hud that show up temporarily. Delete as much as you want. I suggest keeping the crosshair folder though as playing without it is difficult.
To remove text popups when you collect health, etc, find the data1.fbz file. Rename it to data1.zip.
Open that file with a text editor. Remove all the text on the right side of the "=" signs that you want gone from the game.
Save the file.
Repack all the files and name the new zip file data1.fbz. Put it back in the Trine directory. Start the game and the text will no longer appear.
To remove other text, edit the updates_afterlokit1.loc
Make sure to rename the other data2.fbz and data3.fbz to something else. They contain redundant information which may negate edits.