How do I show/hide the HUD in Scrap Mechanic?
Although not shown in the controls menu, the key combination Alt+Z will show/hide your HUD.
To change this keybind, you will need to edit the Keybind.Json file located here: %AppData%\Roaming\Axolot Games\Scrap Mechanic\User\User_[numbers].
If you scroll down you will see the following:
K means which key is needed to be pressed. It has a value of 90 which translates to Z according to this website. You can change 90 to whatever number corresponds with the letter you wish to press. You can then also change "Alt" to "Shift" or whatever else you desire the keybind to be.