Hanging Arrows bug - TTLG Forums

fortuni on 21/1/2022 at 01:31

vfig recently started a (https://www.ttlg.com/forums/showthread.php?t=151613) new thread over at the Editors Guild asking if anyone knew how to prevent arrows hanging in the air after shooting them from your quiver. This is an ancient Thief engine bug that has plagued players since the early days.

Various authors looked into this problem and discovered it that objects flagged as doors that also have the "Sphere" or "Sphere Hat" physics model type cause this problem.

Jax has now made a couple of test dml's for both Keeper of the Prophesies and for What Lies Below, missions that experience this bug and the solution appears to work. The fix is easy to implement now we know what the problem is AND it appears that we can use the same fix for bodies that hang in the air after knocking out AI's

Whilst bug testing I have come across hanging arrows and floating bodies too many times to count, but stopped reporting this bug over at Shadowbox because no solution was available, so we need your help in identifying missions that have this bug, if you know of any missions that could benefit from this fix or come across this bug in the coming months please post below or PM myself or Jax and we'll make dml's for them.

Known Missions
Burrick's Head Inn................Fixed
Keeper of the Prophesies (Insurrection + The Other Side of Time)...........Fixed
The Mirror..............Fixed
Mirror of Return............Fixed
Pereira's Mansion.............Fixed with older dml
Rose Garden....................Fixed
Rowena's Curse...............Fixed
Ruined (mission 1+2)................Fixed
What Lies Below................Fixed
Korrigans................Fixed
The Sun without, The Sun within.......Fixed

downwinder on 21/1/2022 at 05:30

i personally love the floating arrows in fan missions/thief universe it shows magic is strong

nicked on 21/1/2022 at 07:38

Rowena's Curse was another one that was mentioned as having this bug.

vfig on 21/1/2022 at 09:27

thanks, fortuni! i wasnt sure, having no yet tried it, it if a dml that just fixed the model type would be sufficient (since changing the model type in dromed can sometimes reset other physics properties). but i just tried your rose garden dml and loaded the savegame up in dromed afterwards to inspect, and the other physics properties are all looking fine. so im glad its less fiddly to fix than i feared.

fortuni on 21/1/2022 at 10:16

FYI this is what Jax posted over at Shadowbox

Code:

There is a (https://www.ttlg.com/forums/showthread.php?t=151613) new thread on The Editors' Guild detailing an issue involving arrows hanging in the air after being fired in some missions.
In short, objects flagged as doors that also have the "Sphere" or "Sphere Hat" physics model type cause this problem.
This is because the game assumes that all doors have the "OBB" model type in the mathematics pertaining to projectile collision with doors.
While all doors should have "OBB" set as their physics model type, this is a faulty assumption because it is possible to set up an object that is considered a door and also has a different model type.
More specifically, this becomes a problem because the size of the door object is retrieved from the vector contained within the "Size" field of the physics model
dimensions property.
On an object with the "OBB" model type, this is valid and the calculation is correct.
However, on an object with the "Sphere" or "Sphere Hat" model type, the "Size" field of this property will be a zero vector because the dimensions for these model types make use of different fields
("Radius 1" and "Radius 2" for the "Sphere" type and just "Radius 1" for the "Sphere Hat" type). As a result of this, the calculation is incorrect and results in this phenomenon.
Some of this information is not included in the thread at TTLG, so perhaps it would be prudent to provide this explanation there as well.

There are multiple ways that we could go about fixing this in missions. Firstly, it is worth noting that the engine gives the door physics model flag (kPMF_Door)
to any physical object with either the "RotDoor" or "TransDoor" property.
Additionally, this flag must be present for the mentioned calculation to occur. Consequently, if these properties do not need to be on the object, one option is to simply remove the property.
However, doing just this will not be enough to solve the issue, as the object must be rephysicalized in order to reinstantiate the phisics model and get rid of the door physics model flag.
Alternatively, if reasonable for the particular object, we can just remove the door property and disable collisions entirely by removing its physics type as well. If the object requires the door property,
another option is to set the physics model type of the object to "OBB", as this will populate the "Size" field of the physics dimensions property and allow the calculation to proceed correctly.
Both of these approaches should remedy the problem.

baeuchlein on 21/1/2022 at 22:02

"The Burrick's Head Inn" is another suspect. When playing the first version of this mission with Thief 2 before NewDark, I had the arrows I shot, after the final fight of two enemies, stuck in the air, and after a while, my computer ran slower and slower. It did happen only once, and I did not experience it again either with the first version of the mission or the v2.0 and the "Vintage edition".

On a side note... In v2.0 (still in pre-NewDark times), if I blackjacked the two guards in the lobby, and then used the bell near the receptionist's desk, the two guys teleported to this place again - still unconscious and hovering at about waist height. I have seen some similar things with my dead and unconscious victims in other missions where some action (pressing a button, opening a door, etc.) made them appear at a certain location, thus I guess this is not the same problem as the "Hanging arrows bug" - but I'll leave the final decision about that to you.

downwinder on 22/1/2022 at 00:17

if you get hanging arrows while in mission from you shooting arrows,a simple fix is save then close out thief completely and restart the arrows will work then

but if you play a mission when there is a random arrow just sitting in air and you did not shoot it/nor a npc shoot it, that is magic,and i don't mean a arrow that should be stuck into a item and author placed it a bit away from item ,but a arrow say in air in the middle of a forest/etc

baeuchlein on 22/1/2022 at 00:41

The first post in this thread states that it is about arrows hanging in the air after the player shoots them from his/her quiver. Also, I think I had about 50 to 100 hanging arrows in "The Burrick's Head Inn" (I re-collected them to stop the notable lag caused by them), thus it's not just one single weird one.

Reloading the saved game with that enormous amout of hanging arrows did not work back then. Restarting the whole mission did. But imagine how funny this is if you almost completed long missions like "Rowena's Curse", but then they turn into "Arrows' Curse(s)", and you have to start all over again.:nono:

fortuni on 22/1/2022 at 00:58

Quote Posted by downwinder

Downwinder it not magic, it's a annoying bug that has existed in Thief from the very early days, and closing your game and reloaded is not a solution, but pure chance that the bug didn't reoccur. As for rogue arrows again they're not magic either but misplaced objects, we remove them when we find them.

@ baeuchlein
Thanks for the input.

vfig on 26/1/2022 at 14:08

another fm showing this problem: The Mirror of Return Part 2. i got hanging rope arrows while playing it, checked the mission in dromed, and sure enough it has several Door: Translating objects with Sphere physics. i think theyre for its teleporter rings.

incidentally I also had several encounters with objects that i couldnt drop or throw after picking up, just stuck in my hands - a crate, a bedroll, and a torch. each resolved itself after either a reload or relaunch of the game. i dont know if this is also a side effect of the spherical door issue, or unrelated object breakage.