I FOUND IT!
I had typo errors in the code snippet. Here is a copy-and paste:
desc = counter (blood-splat)
;triggers
:activated=1:incstate=1,activate=0
:state=3:activateifused=1
;end script
Each object I pick up has in the Main any of the standard pickup.fpi but you have to add activateifused=1 like this;
desc = Pickup Item and activate
;Triggers
:state=0:hudreset,hudx=50,hudy=90,hudimagefine=gamecore\text\pickedupanitem.tga,hudname=itemprompt,hudhide=1,hudmake=display,state=10
:state=10,plrdistwithin=40:state=1,playertake,coloff,plrsound=audiobank\misc\ping.wav,hudshow=itemprompt,hudfadeout=itemprompt,activateifused=1
:state=1:rundecal=5
;End of Script
Place any entity as a counter in the map editor such as spat-blood and give it as main the above counter code snippet and If Used= the-name-of-the-door-to-be-open.
The door should have as Main doorremote.fpi and as Use Key the-name-of-your-counter-entity
I find this script very useful because tou can use the same coding for 3 objects or 5 or any number simply bu changing the counter code above to that number ei; state=7 in place of state=3 for 7 objects you got to pickup.
Furthermore you can also count enemies killed and open the door only when they are all (3,5,etc) are killed.
