To summarize things related to hitreg, netcode, lag, lag compensation and other things. If someone has more to add, or videos/screens to contribute to some issue (or even to invalidate some issues) just post below.
1. General things one should know about:
a) Update rate is fixed to 20 ( i.e. once per 50ms)
b) Interp is at 100ms (can be changed by some server mods)
c) What you see is what you hit approach; marines can you shoot you if they see you on your screen, even if you aren't
d) Hitbox is close to the model (more of a simplified model; Skulk)
e) There have been some issues with hitreg in the past that have been fixed, such as the animation issue (hitreg being off when animation plays)
f) LMG has random spread (close range*, far range*)
g) Shotgun has fixed, but randomly rotating spread (8 pellets out, 8 pellets inner circle, 1 middle; close range, far range)
2. Non hitreg/netcode Issues:
a) Skulk head is too small for all shotgun pellets to hit; i.e. you can not oneshot a skulk from front unless in your face
b) LMG spread can make you miss with good aim, especially on range
c) LMG has a "double-fire" issue, it fires twice when you press your mouse once (sometimes), so it's possible to miss two (or hit two) shots with just fireing once
d) There seems to be slight input lag from "firing" and actually "shooting"; most noticeable with shotgun
3. Issues:
a) Server tickrate breaking in will affect hitreg/compensation negatively, a server not running at 30 tick, will cause some shots or pellets to miss
b) Packet loss can potentially cause players to warp around "lag", resulting in hard-to-hit players
c) Players with high ping, still can shoot what they see, itensifiying the "i've been killed around a corner"
d) Hit feedback is slow/delayed, causing you to notice damage only after several bullets have been shoot (due to high interp etc); possibly more stuff causing it to be delayed further besides netcode
e) Sometimes (tm!) shooting a player that is very close to you will cause all bullets to miss; you can replicate this with bots or players, doesn't seem to matter. I suspect this might be due to either that you're "dead" on the server already or some issue with collisions (i.e. other model glitching though yours). This is VERY bad with shotgun, as it can make a sure-kill into a 0-dmg you're-dead nightmare
f) Fixed updaterate should be acutally be modifiyable
z) Other unaccounted for issues that make bullets miss/not register properly (visible hitsprites, but no dmg); also see below
4. Suspected issues:
a) Low FPS seems also like a possible cause warping
Might be due to lower updaterate and inconsitency in the frames. Frames below 20 should not be able to send enough updates, and bumpy fps might send updates irreguarily causing "inconsistent" behaviour in the hitreg.
b) It seems that higher server load (increased player count) causes hitreg to suffer;
Even with a stable 30 tickrate and cpu < 100%, it seems that it becomes significantly worse as the load increases on the server applicated.
It might have to do somthing with frame/tick discrepancy, which means that some frames/tick take siginificantly longer to calcuate then others; example:
Tickrate 4 (for simplicity); each frame should take 250 ms:
Tick 1: 250ms - normal
Tick 2: 450ms - tick took significantly longer then expected
Tick 3: 100ms - tick took significantly less then expected
Tick 4: 200ms - tick took sightly less then expected
This would result in inconsistent results, as some things proccessed in tick 2 for example would take longer then otherwise; I think might also cause bullets to "disappear" or behave wierd. Also other unaccounted for issues.
I'm guessing this happens because you see odd behaviour on FULL, BUSY and LARGE servers, such as 24 player game is usually much worse then a 12 game, even if the server doesn't "lag" and runs at tickrate 30; chances are that some ticks simply take much longer then others to process causing the issue.
Notes:
* The position in the lmg spread screenshots is not related to the range shot from - I've actually moved closer for a more visible result![:P]( ":P")
1. General things one should know about:
a) Update rate is fixed to 20 ( i.e. once per 50ms)
b) Interp is at 100ms (can be changed by some server mods)
c) What you see is what you hit approach; marines can you shoot you if they see you on your screen, even if you aren't
d) Hitbox is close to the model (more of a simplified model; Skulk)
e) There have been some issues with hitreg in the past that have been fixed, such as the animation issue (hitreg being off when animation plays)
f) LMG has random spread (close range*, far range*)
g) Shotgun has fixed, but randomly rotating spread (8 pellets out, 8 pellets inner circle, 1 middle; close range, far range)
2. Non hitreg/netcode Issues:
a) Skulk head is too small for all shotgun pellets to hit; i.e. you can not oneshot a skulk from front unless in your face
b) LMG spread can make you miss with good aim, especially on range
c) LMG has a "double-fire" issue, it fires twice when you press your mouse once (sometimes), so it's possible to miss two (or hit two) shots with just fireing once
d) There seems to be slight input lag from "firing" and actually "shooting"; most noticeable with shotgun
3. Issues:
a) Server tickrate breaking in will affect hitreg/compensation negatively, a server not running at 30 tick, will cause some shots or pellets to miss
b) Packet loss can potentially cause players to warp around "lag", resulting in hard-to-hit players
c) Players with high ping, still can shoot what they see, itensifiying the "i've been killed around a corner"
d) Hit feedback is slow/delayed, causing you to notice damage only after several bullets have been shoot (due to high interp etc); possibly more stuff causing it to be delayed further besides netcode
e) Sometimes (tm!) shooting a player that is very close to you will cause all bullets to miss; you can replicate this with bots or players, doesn't seem to matter. I suspect this might be due to either that you're "dead" on the server already or some issue with collisions (i.e. other model glitching though yours). This is VERY bad with shotgun, as it can make a sure-kill into a 0-dmg you're-dead nightmare
f) Fixed updaterate should be acutally be modifiyable
z) Other unaccounted for issues that make bullets miss/not register properly (visible hitsprites, but no dmg); also see below
4. Suspected issues:
a) Low FPS seems also like a possible cause warping
Might be due to lower updaterate and inconsitency in the frames. Frames below 20 should not be able to send enough updates, and bumpy fps might send updates irreguarily causing "inconsistent" behaviour in the hitreg.
b) It seems that higher server load (increased player count) causes hitreg to suffer;
Even with a stable 30 tickrate and cpu < 100%, it seems that it becomes significantly worse as the load increases on the server applicated.
It might have to do somthing with frame/tick discrepancy, which means that some frames/tick take siginificantly longer to calcuate then others; example:
Tickrate 4 (for simplicity); each frame should take 250 ms:
Tick 1: 250ms - normal
Tick 2: 450ms - tick took significantly longer then expected
Tick 3: 100ms - tick took significantly less then expected
Tick 4: 200ms - tick took sightly less then expected
This would result in inconsistent results, as some things proccessed in tick 2 for example would take longer then otherwise; I think might also cause bullets to "disappear" or behave wierd. Also other unaccounted for issues.
I'm guessing this happens because you see odd behaviour on FULL, BUSY and LARGE servers, such as 24 player game is usually much worse then a 12 game, even if the server doesn't "lag" and runs at tickrate 30; chances are that some ticks simply take much longer then others to process causing the issue.
Notes:
* The position in the lmg spread screenshots is not related to the range shot from - I've actually moved closer for a more visible result
