SetLineMonsterBlocking
From ZDoom Wiki
void SetLineMonsterBlocking(int lineid, int setting);
Usage
Sets blocking for monsters only. This has two settings, 0 for off and 1 for on. For readability you should use ON or OFF which are defined as 1 and 0 (respectively) in zdefs.acs.
Examples
This example will set all lines with the id of 1 to block monsters until some catastrophic thing happens five minutes into the map which allows the monsters to penetrate those lines.
script 1 open
{
SetLineMonsterBlocking(1, 1);
delay(35 * 60 * 5);
SetLineMonsterBlocking(1, 0);
HUDMessageBold(s:"ZOMG! The monsters can break through now!!!";
HUDMSG_FADEOUT, 1, CR_RED, 0.5, 0.5, 3.0, 1.0);
}

