Uploaded November 2020 | Updated September 2026, 1 hour ago
Since a couple of years, Portal 1 runners remarked a strange and rare phenomenon in which the door in 05 would open on itself at map load.
Recently, a beginner questioned me about a strange fact: one of his mate could do a trick in 3420, but he can't replicate in 5135. Listening to my courage and wisdom, I decided to investigate on it.
I figured out, that the softlock trigger that opens the door requires a filter entity called filter_weight_box. This trigger is present in 5135 ("Unpack" build) and Steampipe ("Steam" version), but not in 3420 ("Old Unpack" build). I then figured out that the issue was not on the map itself (not on the .bsp, that were slightly different, but neither had a filter_weight_box). That the filter_weight_box were hardcoded (with the help of FabiClawZ) to the map itself, while loading the radios. Then I conjectured that the map would load, then that it could sometimes not load the filter, then it loads the radio. The radio is INSIDE the trigger. The trigger is touched by a prop, but not filter to tell whether it is a box or not is present, so no filter is applied; hence, the dialogue triggers and the door opens.
After this conjecture, we had to prove it, and in this video, UncraftedName demonstrates a real experiment with what could have happened in those rare cases in which the softlock trigger would trigger on map spawn with the help of CheatEngine. This is not a straight-forward proof, but yet a solid argument to explain this phenomenon.
filter_weight_box is ABSENT in 3420, PRESENT in 5135, PRESENT in Steampipe. Hence, you can't get softlock dialogue in 3420, only in 5135 and Steampipe.
Function name in C Called: CSpawnDinosaurHack::ApplyMapSpecificHacks()
(yes, it is called like that in the game code)
CheatEngine value: 33 c0 eb 05 1b c0 83 d8 ff 85 c0 75 46
Shoutouts to UncraftedName and Fabi for helping me on this.
Since a couple of years, Portal 1 runners remarked a strange and rare phenomenon in which the door in 05 would open on itself at map load.
Recently, a beginner questioned me about a strange fact: one of his mate could do a trick in 3420, but he can't replicate in 5135. Listening to my courage and wisdom, I decided to investigate on it.
I figured out, that the softlock trigger that opens the door requires a filter entity called filter_weight_box. This trigger is present in 5135 ("Unpack" build) and Steampipe ("Steam" version), but not in 3420 ("Old Unpack" build). I then figured out that the issue was not on the map itself (not on the .bsp, that were slightly different, but neither had a filter_weight_box). That the filter_weight_box were hardcoded (with the help of FabiClawZ) to the map itself, while loading the radios. Then I conjectured that the map would load, then that it could sometimes not load the filter, then it loads the radio. The radio is INSIDE the trigger. The trigger is touched by a prop, but not filter to tell whether it is a box or not is present, so no filter is applied; hence, the dialogue triggers and the door opens.
After this conjecture, we had to prove it, and in this video, UncraftedName demonstrates a real experiment with what could have happened in those rare cases in which the softlock trigger would trigger on map spawn with the help of CheatEngine. This is not a straight-forward proof, but yet a solid argument to explain this phenomenon.
filter_weight_box is ABSENT in 3420, PRESENT in 5135, PRESENT in Steampipe. Hence, you can't get softlock dialogue in 3420, only in 5135 and Steampipe.
Function name in C Called: CSpawnDinosaurHack::ApplyMapSpecificHacks()
(yes, it is called like that in the game code)
CheatEngine value: 33 c0 eb 05 1b c0 83 d8 ff 85 c0 75 46
Shoutouts to UncraftedName and Fabi for helping me on this.
