Streamer casually falling into the Void

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pango
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Streamer casually falling into the Void

Post by pango »

... while walking into a Shedungent corridor. I'm puzzled, first time I see that...

https://www.twitch.tv/videos/823107109?t=7h54m18s

Daggerfall Unity 0.10.27 with no mods, as far as I can tell.
Game has been running for about 9 hours, maybe that matters.

It didn't happen in the same spot after reloading, and in fact it only happened once in the whole session.

Of course it'll probably be very hard to reproduce :(
Last edited by pango on Thu Dec 03, 2020 7:30 pm, edited 1 time in total.
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Ralzar
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Re: Streamer casually falling into the Void

Post by Ralzar »

Falling through the floor has been happening noticeably more lately. Not sure if it started with 25, 26 or 27. Usually when entering a house though. I don't think I've had something as extreme as that happen.

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pango
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Re: Streamer casually falling into the Void

Post by pango »

Unity 2019.4.x collision detection working better in general, until it doesn't? Mmmh
That really needs a reproducible case...
Last edited by pango on Thu Dec 03, 2020 12:08 pm, edited 1 time in total.
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Ralzar
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Re: Streamer casually falling into the Void

Post by Ralzar »

I suspect some kind of small gaps have appeared between surfaces, but that's pure guessing from my side.

I noticed Hazelnuts Travel Options mod also has a lot of problems with falling through the ground. A lot more than Tedious Travel used to have, despite a lot of that code being taken directly from Tedious Travel. Which I suspect is really caused by Travel Options being released with the new DFU engine version.

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pango
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Re: Streamer casually falling into the Void

Post by pango »

But player collider is a capsule, so small gaps should be no big deal.
I have no good hypothesis, in above case this really looks like a bug (or new requirements) in Unity (or PhysX)...
Last edited by pango on Thu Dec 03, 2020 6:16 pm, edited 2 times in total.
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ACNAero
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Re: Streamer casually falling into the Void

Post by ACNAero »

I’ll give my anecdotal experience here if it helps at all. I’ve noticed this has been an issue for me since 0.10.25 (and hasn’t been an issue for me since 0.7), and here’s what I can remember of them happening:
-Most of them are in dungeons (roughly ten times total) where I’ll just walk into a room and suddenly fall out the bottom, both with a large mod loadout (lots of graphics mods and landmass changers) and with a minimalist loadout (very few graphics mods, no landmass changer, and retro rendering).
-Once when teleporting from a dungeon to the Mage’s Guild
-Once when walking into a building (I think either a store or a temple).

In all these instances, I could cast levitation and freely go above and below the ground. So my guess is that the collision data isn’t always loading in properly/completely. Only reason I never reported it is because the issue is resolved by either saving and loading or exiting and re-entering the building, so posting a save file is completely unhelpful.

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Interkarma
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Re: Streamer casually falling into the Void

Post by Interkarma »

This was a Unity issue way back in the early days where collider data wasn't correctly added, or CapsuleCollider vs. MeshCollider was intermittently broken. Some geometry would just randomly be non-collidable to player. It was fixed in the 2018 version we used prior to now. Disappointing to see that issue might have returned. Will monitor this, thanks for raising Pango.

When it comes to falling through terrain with time acceleration (e.g. from Travel Options) that's a separate issue. Whenever your Speed > FrameSpeed, you risk desyncing from the physics simulation. This isn't something we can fix, the user should be careful about their time settings relative to hardware.

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Ferital
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Re: Streamer casually falling into the Void

Post by Ferital »

Well at least, falling into the void looks better in DFU than in classic :)

If someone is able to reproduce this, it might be good to check if this still happens with Unity 2019.4.16f1.

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Hazelnut
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Re: Streamer casually falling into the Void

Post by Hazelnut »

Interkarma wrote: Thu Dec 03, 2020 11:52 pm When it comes to falling through terrain with time acceleration (e.g. from Travel Options) that's a separate issue. Whenever your Speed > FrameSpeed, you risk desyncing from the physics simulation. This isn't something we can fix, the user should be careful about their time settings relative to hardware.
FYI, I did some more investigations into this and I think our theories are incorrect. I didn't bother you with it at the time because you had too much on your plate but I'll make a thread in Dev forums about it when I have the time to explain what i think might be happening because I couldn't figure out the code well enough to fix it myself... it's going to need your attention Interkarma I think.
See my mod code for examples of how to change various aspects of DFU: https://github.com/ajrb/dfunity-mods

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Interkarma
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Re: Streamer casually falling into the Void

Post by Interkarma »

Fast moving colliders absolutely miss collision tests. It's a really well known phenomenon of physics simulation called tunneling. Have a Google about to see what I mean.

https://www.google.com/search?q=unity+f ... +collision

It happens because fast objects step through space in larger increments than the physics integration can resolve per tick. Unity has some means of overcoming, like swept tests, but not sure they can apply to character controller. It has a whole other thing going on.

You'd have to provide some really solid testing to convince me that's not the issue. ;)

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