Havok 4 Beta and Dynamic linkset limit

Woot! Hopefully this is NOT a bug, but so far the primitive linkset max for physics has been increased to 64!

Yay!! Don't believe me? Come to the Havok 4 Beta grid and test it out! pretty sweet! Better vehicles!!!

Hopefully this is one thing that DOES carry forward....

So far, looking great! A lot of bugs still, but I am feeling good about this )

omg omg omg omg! yay! I have been dying for beta grid to open back up, now im just bubbling over with all that warm stuff that a carebear is in the world for! woot!

I thought on the blog it said that it was limited to 31 prims still for vehicles

I'm curious, never had been to the Beta Grid before today. Don't know if it was where I was, or if it's an issue, but the test vehicles I brought out seemed extremely sluggish in both control inputs and top speed. The vehicles were all, "lightly scripted", just variants on some of the basic Linden vehicle scripts. Did anyone else experience this?

Yeah, I've been experiencing it too. Physical objects seem very underpowered in the new physics engine. Vehicles behave very sluggishly and my elevators are unable to ascend.

Cubey Terra posted an issue to Jira here:
http://jira.secondlife.com/browse/SVC-722

Yup,

Warning with 70-Prims:
Script can't enable physics for objects with more than 64 primitives

63 Prims works OK (one driver)

I'm not sure if the slowdown isn't just lag, I found a quiet corner of a quiet SIM (Kissling) and my car seemed to drive no worse than the main grid. Theres a lot of lag elsewhere due to people running 'physics test', even then, I'm amazed that some of the physical test I've seen still let me move around without crashing.

I'm actually starting to feel a spark of excitement about SL again after many months of watching it die.

I just took one of my Yosu Mk2 single seat cars down to Beta. It is 30 prims, so I made a test object out of 30 small steel balls and stuck it on the back of the car and it was still driveable with no noticeable change in performance.


So, so sum up - at the moment on Havoc4 Beta, a 60prim linked vehicle is driveable - definitely - I did it with me own hands!!!!!

I'm hoping that LL is only saying that the dynamic link limit is still 31 in case this new limit doesn't work out, so that people can't complain later on. That said, I hope the limit on the main grid will change to 64 - with more than double the prims, so much more is possible without resorting to attachments!

Maybe they are just trialling the 64, but will limit it for a while to 31 again, till other bugs are sorted.

Or to give some users time to update their computers to something that can handle complex collision calculations?

Actually, 128 (or maybe it was 256) prim physical vehicles are "possible" on the main grid right now. I watched someone produce a working one a few minutes before the meeting with the Lindens last Sunday. The reason the limit is set to 32 right now is because Havok 1 is woefully inefficient at making the calculations. It can be done, but it's just too expensive for everyone to be allowed to do it. I didn't get a chance to ask what forbidden magick the person used to bypass the limit on the main grid, but I did get to ride it and it was surprisingly smooth.

In either case, I do hope the 64 limit on the beta gets solidified. A bunch of my vehicles are just a few over the current limit... so frustrating.

Are there any void/open-space sims on the beta-grid? I don't suppose anyone's tried to overload the physics on one of those? Or all the ones in a single cluster, to see how they perform?

Linden developer 'Andrew' said that the limit is still 31 with SL & Havok 4, not because of Havok4 limitations, but because of sim crossings:

"The prim limit for dynamic objects is 31. The reason the limit was not
changed in Havok4 is the border crossing problem, which is unrelated
to the physics engine. The more primitives in an object (and scripts,
and object contents, etc) the longer it takes save/load the object
across the border. We'll be tackling that problem later -- reducing
the crashes is more important"

They said that they will not introduce new features when havok 4 is introduced at the main grid. But that they will work on the feature enhancements later (thanks to the 'Project Open Letter').

Physics is NOT calculated client side. Users do not have to update their hardware.

I tested out some physics devices in an empty sim and found that the current implementation on the Beta grid is 2-5 times slower than normal (subjective).

The Ls have finally admitted that there is something that is causing it to be very slow currently, they didn't say what, may be the abstraction layer they added or something in the implementation, they "assure" us that it is NOT Havok 4 that is slow.

But yes for now, depending on what you are doing, the physics on the beta grid are somewhat to MASSIVELY slower than on the main grid.

Looking forward to that being fixed, the one good part was that it did seem to be much less crashy, if that alone is the only change in the end it will be worth it. I've been forced to NOT sell products because of the physics engine crashyness and could not in good conscience sell something that would accidentally crash the sim simply by behaving correctly

Most likely they were doing the well known trick of having a 31 prim physical vehicle, but also utilizing an attachment of up to 255 prims which attaches at the waist. So it appears the vehicle is way over the physical limit, however it's just a clever illusion.

See, the thing is I actually rode it. Nothing attached or gave inventory to me when I sat on it.

The vehicle itself was nothing but a bunch of small cubes linked as one. No clever texturing, just prims. I counted them in the general tab of edit mode. O_o

Um, not nessesarily... there are a few of these shocker physical linksets out there. There was a bug, many moons ago, that allowed folks to "phys" any linkset. They remain physical now, they just won't return to physical if you turn physical off.

I have a 127 prim airplane that flys with physics, for instance.

Seems to work on the beta grid

I see. Well, naturally i was talking of normal items, not bugged ones The limit is purely arbitrary it's true, designed to prevent lag and sim overload, not because it's impossible to do.

This is exciting news and may spark an old SLers interest in SL again among the other factors! Hopefully they get the 64 working fine and bump it more like they said they would long long ago and that was when Hav 3 was the option! *fingers crossed*

If it's the abstraction layer, just don't use it. That should tell you right away whether or not it is a problem there.