[#SVC-736] Havok 4 Vehicle Bugs - Rezzing & Damping

2. Second Life Service - SVC

Havok 4 Vehicle Bugs - Rezzing & Damping

Created: 29/Sep/07 11:08 AM Updated: 17/Feb/08 02:52 AM

Component/s:

Physics

Affects Version/s:

Havok4 Beta

Fix Version/s:

Havok4 Beta

Environment:

Server Side bug

Issue Links:

Duplicate

This issue duplicates:

~~SVC-722~~ Havok 4 general vehicle problems (list)

Relates

This issue Relates to:

~~SVC-1185~~ llGetMass() and llGetCenterOfMass() incorrectly reports a objects mass after being sat upon by an avatar

This issue is related to by:

~~SVC-1567~~ buoyancy values aren't the same for moving objects

~~SVC-832~~ Havok4: General Ground Vehicle Problems

~~SVC-775~~ VEHICLE_REFERENCE_FRAME broken on preview

Description

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Havok 4 Seems to have some weird bugs when relating to vehicles that are somewhat hard to describe. My own testing focuses on the Dominus Shadow. (If any Lindens would like a copy, you can IM me)

Background: The Dominus Shadow has two travelling modes - driving along the ground, and flying as a hovercar. Since Andrew posted on the blog that ground vehicles are currently broken, I've not bothered testing ground mode.

Tested in Sandbox Island - completely flat ground, no prims

Hovering problems:

Something's wrong with the collision bounding box. Like it's at an angle or something.
If you fly in the air, and then fly straight down against the ground (push the pg down key) your vehicle starts to twitch against the ground, like there's an invisible barrier or something. (the ground is real SL terrain, and it's completely flat)
If you turn, the vehicle just sinks to the ground.
momentum/air friction seems off. In Havok 1, if you travel forward/sideways you quickly come to a rest. In havok4, you just glide around forever. This same behaviour seems to apply to rotational momentum too.
There seems to be something funny with buoyancy. If I turn off the code that makes the car bob, the hovercar just sinks to the ground.

[edit: Add this section]
New Problems:

With the current version of havok on the grid, if you rez a Dominus Shadow below 768m, the entire model gets screwed up. (Very bad!)
Strafing left/right in havok1 results in a flat left/right motion. Now in havok4, it results in left/right motion AND travelling upwards.
Possible explanation:
The angular motor is weaker
The vertical attractor is now more powerful

[Edit: The object count seems to be fixed]
Unrelated:
Currently, the sim stats in Sandbox Island is reporting -1066 objects.

Unrelated but I don't know where else to ask:
I've been having a lot of trouble finding a sims that aren't lagged to test in. Would it be possible to have a sim where testing havok4 by "rezzing a million physical things" is discouraged?
[Edit: Thanks for the test sandbox Andrew!]

That's it for now, thanks

Description

Havok 4 Seems to have some weird bugs when relating to vehicles that are somewhat hard to describe. My own testing focuses on the Dominus Shadow. (If any Lindens would like a copy, you can IM me) Background: The Dominus Shadow has two travelling modes - driving along the ground, and flying as a hovercar. Since Andrew posted on the blog that ground vehicles are currently broken, I've not bothered testing ground mode. Tested in Sandbox Island - completely flat ground, no prims Hovering problems:

Something's wrong with the collision bounding box. Like it's at an angle or something. If you fly in the air, and then fly straight down against the ground (push the pg down key) your vehicle starts to twitch against the ground, like there's an invisible barrier or something. (the ground is real SL terrain, and it's completely flat)
If you turn, the vehicle just sinks to the ground.
momentum/air friction seems off. In Havok 1, if you travel forward/sideways you quickly come to a rest. In havok4, you just glide around forever. This same behaviour seems to apply to rotational momentum too.
There seems to be something funny with buoyancy. If I turn off the code that makes the car bob, the hovercar just sinks to the ground.

[edit: Add this section] New Problems:

With the current version of havok on the grid, if you rez a Dominus Shadow below 768m, the entire model gets screwed up. (Very bad!)
Strafing left/right in havok1 results in a flat left/right motion. Now in havok4, it results in left/right motion AND travelling upwards. Possible explanation:
The angular motor is weaker
The vertical attractor is now more powerful

Some things don't seem rezzable. For instance, if you try and open the doors, you get the error message: " Unable to create requested object - parse failure." Looking further into it, some items are simply not rezzable with this error. If you get the object, "Door Open Frame" from the contents of a Dominus Shadow, and you drag it into your avatar's inventory, and then try and rez it, you get this error message. [Edit: The object count seems to be fixed] Unrelated: Currently, the sim stats in Sandbox Island is reporting -1066 objects. Unrelated but I don't know where else to ask: I've been having a lot of trouble finding a sims that aren't lagged to test in. Would it be possible to have a sim where testing havok4 by "rezzing a million physical things" is discouraged? [Edit: Thanks for the test sandbox Andrew!] That's it for now, thanks

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Francis Chung added a comment - 01/Oct/07 12:09 AM

How do I change the Issue Links? It was incorrectly marked with a "duplicates" link to ~~SVC-722~~, when it's not - it should be a "relates to" as this includes several independent issues.

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Vincent Nacon added a comment - 15/Oct/07 09:33 PM

well crap, didn't mean to link this as duplicates jira report. Should be related instead. If a linden can fix this, that'd be great.

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Andrew Linden added a comment - 19/Oct/07 09:45 AM

Many things have been fixed since this bug was first entered. In particular, I believe the report about -1066 objects in the region has been fixed, the explicit linear damping on objects has been removed, and I just checked in some fixes for vehicles that are not yet deployed to the preview. I'll try to get around to testing a Dominus Shadow to see if I can notice if any of the other things are still wrong. However, if anyone tries the Dominus before me I'd appreciate any update info they might be able to add in these comments. Thanks.

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Francis Chung added a comment - 23/Oct/07 12:13 PM

I have just tested with the latest version of havok. The Object count doesn't seem to be negative anymore.

All of the hovering problems that have been reported are still there.

New Problems:

With the current version of havok on the grid, if you rez a Dominus Shadow below 768m, the entire model gets screwed up. (Very bad!)
Strafing left/right in havok1 results in a flat left/right motion. Now in havok4, it results in left/right motion AND travelling upwards.
Possible explanation:
The angular motor is weaker
The vertical attractor is now more powerful

[ Permlink | « Hide ]

Andrew Linden added a comment - 26/Oct/07 03:27 PM

I just fixed a problem where the center of mass was incorrectly placed at the center of the root prim. This was a bug that was introduced a couple of weeks ago when a LL developer made an optimization pass and started bypassing some recomputes of the object mass that sometimes bypassed legitimate instances. I suspect this fixes a lot of the problems people have been seeing with vehicles.

Not only is this fixed in the internal codebase, but I deployed it to a limited set of regions in the Havok4 preview for the pre-halloween weekend: "Bug Island" and "Da Boom". I'd appreciate it if someone could make some preliminary testing to see if any of these problems are fixed, thanks.

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Andrew Linden added a comment - 30/Oct/07 08:40 AM

I suspect some of the bugs mentioned here are related to ~~SVC-898~~.

Also, there was a bug fixed in the vehicle code where the VEHICLE_ANGULAR_FRICTION feature was not being properly handled which would break some vehilces, perhaps even making them difficult to control if they were relying on heavy friction to compensate for similarly heavy-handed steering settings, such as the "Zanshin Hovercar".

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Bato Brendel added a comment - 12/Jan/08 10:52 AM

I dont know if anyone has reported this or even noticed this, but mass is completely messed up in havok4. llGetMass() will report on a 1m³ cube as it should 10.000006 in mass. But when you sit on the objects it will end up reporting only the avatars mass. I dont know how the inner workings of dampening/hover/bouyancy work but this major miss reporting of a objects mass can not be a good thing. I got demonstration touch script prims with open source code @ the periwinkle sim that report its center of mass, mass, your mass and a few other nice debugging info pieces of data and there is clearly a major issue with the calculation of mass of objects after they are sat upon, even the Center of Gravity is a issue between the normal havok and H4.. Ive been searching thru Jira if this has been posted and so far I havent come acrost it so Im probally going to open a ticket for this.

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Andrew Linden added a comment - 14/Jan/08 08:38 AM

The incorrect mass (and inertia) bug is known is is already fixed in the most current snapshot of the codebase. The fix will be deployed sometime this week.

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Andrew Linden added a comment - 14/Feb/08 10:08 AM

I'm going to resolve this bug. I was riding a Dominus earlier in the week and it is much improved:

Mouselook works.

Banking works.

Doors open fine.

Dunno about the twitching when hovering down against the terrain, but I suspect that is fixed since I fixed another vehicle that was pushing down against the terrain.

Hover and buoyancy was working for me in general, but I don't know how to turn off the "bobbing" behavior.

Don't open this bug if any of these problems are not fixed. Instead , open a new bug for each broken behavior with instructions on how to reproduce the problem. I've already got a copy of the Dominus so no need to give me a copy.