is this possible? only that the forcefield isnt going to be a door, I want a button to activate the forcefield, so the forcefield effect will turn off and on? how do I do that? or in other words, how do I make the forcefield disappear then re-appear with a button?

Link the button to a func_usable.

Scripting is the solution. Look at the behavEd script below; it allows me to open a door using a wall computer. This door closes itself after 6 seconds. It is not far from what you want to make.

A few notes:

"doorPanelAnim" & "doorPanelNoAnim" are the "targetname" of "func_usable" brushes (the ones of the computer).
"doorPanelAnim" has the spawnflag "startoff" on.
"cargoDoors" is the targetname of the door.

Ignore "holoDoorsCurrentState" & the if/else statement. This is global variable set elsewhere by an other script. Keep both the "dowait" instructions though.

I have placed a "trigger_multiple" brush in front of the computer. "use_button" spawnflag is on. It points to a "target_scriptrunner" entity whose "usescript" key is set to the name of the script below.

There's an easier way than scripting.  Make it a func door with a very high speed, and change the sound it makes.

If it travels its entire visible distance in less than one screen refresh it effectively disappears.

scripting only works in single player. And I belive forcefeilds are available in SP also on HM you have to cheat a little. Use a trigger multiple to open the door and play a sound at the same time. I think you can shut off the sound for the door (maybe not) give the door a lip of 0 and it will disapear. use a force field texture (shader) on it. i think there is a way to make it open with the button and wait till the button gets pushed again to close.