June 2nd, 2004
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Collision fixes collide with servers!
Collision
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- When you are summoned by NPCs or players smaller than you, the collision system will now scan a limited area near the destination to find a place to put you so that you will not be stuck in the terrain.
- A problem related to collision data being out of sync on the client and server has been corrected and should solve the problems many of you have been seeing with NPCs being pushed into walls.
- The sunken NPC and character problem has been much improved. You will still find the occasional NPC at a spawn point that is sunk or elevated slightly, but the NPC should move normally once engaged.
Cabilis Quests
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- The Battle plans from Dalnir should be a little easier to obtain.
- The loyal follower in Dreadlands should no longer be a merchant with an empty inventory.
- The traitor necromancers seek should be a little easier to find.
- Wyzith's belongings should now combine correctly.
-- The EverQuest Team
Patch - 6/02
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Akaran_D
- Way too much time!
- Posts: 4151
- Joined: July 3, 2002, 2:38 pm
- Location: Somewhere in my head...
- Contact:
Patch - 6/02
Akaran of Mistmoore, formerly Akaran of Veeshan
I know I'm good at what I do, but I know I'm not the best.
But I guess that on the other hand, I could be like the rest.
I know I'm good at what I do, but I know I'm not the best.
But I guess that on the other hand, I could be like the rest.
They've been fixing the same damn bugs for 4 years, Yuo'd think they'd eventually find a cure.
Talelor Boreland
* Veeshan Retired *
* Veeshan Retired *
Walls worked pretty well in qvic last night on the one mob we bothered trying it with. We did eventually push it into the wall but it came out easily when the tank tried to move it.
At least it didn't get stuck then start acting like it was rooted/summoning people. From a post I read it seems like the Dev's actually had some clue what was/is causing these problems. I'll see if I can locate it at home as I can't get to that board from work.
Edit: as promised teh post from the Dev's! Copied from shadowknight.org supposed to be somewhere on Sony's boards but I couldn't find it.
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The walled/cornered NPC bug was the direct result of the client and server having two different values for the radius that is used for the collision sphere. This collision sphere is what is used as the basis for where an NPC and player can move. One of the things that changed with the DX9 engine was the introduction of data structures specifically designed to track collision states. The old engine didn't have this. These data structures will (and have) allowed us to make optimizations that the old engine simply couldn't support because it didn't have any concept of persistent collision data; everything was based on the scale of the model and that's it. Anyways, in these data structures the new engine had the collision size set at one point, then the model was scaled, and the bug is that the collision sphere was not also scaled on the server because the server doesn't actually load the model data so it has nothing to scale.. This caused NPCs to have a collision radius of 1.2 on the server for instance where cazic thule in potime on the client was using 4.7 or so. The server would think the NPC is properly cornered but the clients would all think it was on the opposite side of the wall causing a bunch of bugs you all know about by now. Once the collision sizes were synchronized these problems went away. This was also part of the problem with pathing for very small NPCs (the spiders in podisease for instance) because they were constantly getting stuck in the ground due to having a collision sphere on the server *larger* than what the client was using.
On a related note, in the old engine NPCs were actually prevented from going through walls by something unrelated to collision checks of spheres and triangles. It was just doing a point check in legal space, which caused NPCs to be pushable exactly halfway in the wall which made the target point for archery subject to numerical precision errors. And the old collision code had numerous precision errors (one of the many things we just couldn't bring ourselve to port to DX9). In the new engine, it does a proper collision check of the sphere for the NPC against the zone geometry and being halfway in the wall shouldn't occur any more from a mathematical standpoint and this should permanently solve a lot of not-fun archery and other line of sight problems. Animation wise, NPCs will continue to have parts of their body penetrating whatever is nearby, but the collision sphere which is used for all visibility checks and whatnot is definitely kept outside the wall.
Changing the system from something with many inaccuracies that worked only due to CPU intensive redundant safety checks (ie point check in legal space) to something mathematically accurate that doesn't need additional methods to validate behavior is one of the reasons why the new system is better than the old one. It has also made the behavior much more strict which is a large part of why there have been so many "getting stuck" bugs. The system depends on everything always being in a legal state. This isn't always possible however, and I've had to find and correct each possible condition that could put a player "legally" in the position of overlapping geometry. Such as when a door closes on a player; this now has special code to allow the door to be partially disregarded when this happens.. Anyways, it's all very complicated, much more complicated than I think anyone here expected it to become, but I do feel we are nearly done. The remaining bugs - while frustrating to the players for sure - are at least approachable with known solutions (unlike the hard to reproduce stuff we've been dealing with lately) and it's just a matter of getting to them as fast as possible. Once those are taken care of the system will be ready for some very interesting new features that only a properly engineered collision system can support. How exactly we plan to extend it is not something I want to get into yet, right now we need to stay focused on making what we have now work correctly. We're pretty close, I think.
At any rate, we'll be patching the live servers as soon as we are confident these fixes are in fact fixes so for a few more days you can expect the behavior on live servers to remain the same
At least it didn't get stuck then start acting like it was rooted/summoning people. From a post I read it seems like the Dev's actually had some clue what was/is causing these problems. I'll see if I can locate it at home as I can't get to that board from work.
Edit: as promised teh post from the Dev's! Copied from shadowknight.org supposed to be somewhere on Sony's boards but I couldn't find it.
-----------------------
The walled/cornered NPC bug was the direct result of the client and server having two different values for the radius that is used for the collision sphere. This collision sphere is what is used as the basis for where an NPC and player can move. One of the things that changed with the DX9 engine was the introduction of data structures specifically designed to track collision states. The old engine didn't have this. These data structures will (and have) allowed us to make optimizations that the old engine simply couldn't support because it didn't have any concept of persistent collision data; everything was based on the scale of the model and that's it. Anyways, in these data structures the new engine had the collision size set at one point, then the model was scaled, and the bug is that the collision sphere was not also scaled on the server because the server doesn't actually load the model data so it has nothing to scale.. This caused NPCs to have a collision radius of 1.2 on the server for instance where cazic thule in potime on the client was using 4.7 or so. The server would think the NPC is properly cornered but the clients would all think it was on the opposite side of the wall causing a bunch of bugs you all know about by now. Once the collision sizes were synchronized these problems went away. This was also part of the problem with pathing for very small NPCs (the spiders in podisease for instance) because they were constantly getting stuck in the ground due to having a collision sphere on the server *larger* than what the client was using.
On a related note, in the old engine NPCs were actually prevented from going through walls by something unrelated to collision checks of spheres and triangles. It was just doing a point check in legal space, which caused NPCs to be pushable exactly halfway in the wall which made the target point for archery subject to numerical precision errors. And the old collision code had numerous precision errors (one of the many things we just couldn't bring ourselve to port to DX9). In the new engine, it does a proper collision check of the sphere for the NPC against the zone geometry and being halfway in the wall shouldn't occur any more from a mathematical standpoint and this should permanently solve a lot of not-fun archery and other line of sight problems. Animation wise, NPCs will continue to have parts of their body penetrating whatever is nearby, but the collision sphere which is used for all visibility checks and whatnot is definitely kept outside the wall.
Changing the system from something with many inaccuracies that worked only due to CPU intensive redundant safety checks (ie point check in legal space) to something mathematically accurate that doesn't need additional methods to validate behavior is one of the reasons why the new system is better than the old one. It has also made the behavior much more strict which is a large part of why there have been so many "getting stuck" bugs. The system depends on everything always being in a legal state. This isn't always possible however, and I've had to find and correct each possible condition that could put a player "legally" in the position of overlapping geometry. Such as when a door closes on a player; this now has special code to allow the door to be partially disregarded when this happens.. Anyways, it's all very complicated, much more complicated than I think anyone here expected it to become, but I do feel we are nearly done. The remaining bugs - while frustrating to the players for sure - are at least approachable with known solutions (unlike the hard to reproduce stuff we've been dealing with lately) and it's just a matter of getting to them as fast as possible. Once those are taken care of the system will be ready for some very interesting new features that only a properly engineered collision system can support. How exactly we plan to extend it is not something I want to get into yet, right now we need to stay focused on making what we have now work correctly. We're pretty close, I think.
At any rate, we'll be patching the live servers as soon as we are confident these fixes are in fact fixes so for a few more days you can expect the behavior on live servers to remain the same
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Darnik McGee
- No Stars!
- Posts: 1
- Joined: February 16, 2003, 9:11 pm
http://eqforums.station.sony.com/eq/boa ... ge.id=1171 You have to go down about 10ish posts, but it's there.Avryce wrote: Edit: as promised teh post from the Dev's! Copied from shadowknight.org supposed to be somewhere on Sony's boards but I couldn't find it.
Fucking Leezards cant do anything without help
Marshall Darnik McGee Barbarian Warrior - Sovereign