[Opensim-users] Nasty vibration walking on terrain

Sun Mar 1 21:16:00 UTC 2015

It's most noticeable when walking alongside a building. The corner where the building meets the terrain shows the vibration of the view. When the side of the building has a brick texture, this is the worst for causing motion sickness. A thin prim path is also bad because the contrast between the path and the ground makes the vibration more visible. Still, the vibration is always most noticeable when you stop.

Ok.. results from testing:

[BulletSim]
    AvatarHeightLowFudge = 0.8
    AvatarHeightMidFudge = 0.4
    AvatarHeightHighFudge = 0

That's high, lol, but it works. Looking extremely closely with a brick wall beside and a (phantom) brick path below the avatar, these settings gave the following results:

135cm (4'5") avatar: No vibration. This is the shortest shape I can make.

163cm (5'4") avatar: Very very slight vibration visible when I look extremely closely. In normal use I'm sure it would not be seen at all.

200cm (6'7") avatar: No vibration. This is the midpoint of the height range.

264cm (8'8") avatar: No vibration. This is the tallest shape+shoes I can make; tested just in case.

Sizes are as given by the avatar appearance panel.

Unfortunately, with those settings the avatar is way off the ground. I measured 30cm from terrain to sole of the shortest shape. Still, as they prevent vibration, I'll be recommending them to grid owners. I might even go back to terrain on my standalone, but half the builds will need mesh terrain anyway, so there's not much point.

On Sun, Mar 1, 2015, at 09:40 AM, Luisillo Contepomi wrote:
> In my case the vibration is evident only when avatar stop. Others 
> avatars with higth < 120cm. have the vibration all time.
> 
> Luisillo
> 
> 
> 
> El 01/03/2015 a las 3:16, Ethan Grammatikidis escribió:
> >
> > Thank you Mister Blue, that's just the info I was hoping for. I wish I'd
> > waited a little longer to start writing my previous reply.
> >
> >
> > On Sun, Mar 1, 2015, at 01:38 AM, Mister Blue wrote:
> >> I don't see this in my testing but It can easily happen if the avatar
> >> height computation is not exactly synchronized between the simulator
> >> and the viewer[1].
> >>
> >> If you are running BulletSim, the simulator setting you mention is
> >> documented at
> >> http://opensimulator.org/wiki/BulletSim#Adjusting_Avatar_Height . You
> >> can up the AvatarHeightLowFudge a little and see if that helps. if you
> >> have access to the console, you can test values with "physics set
> >> AvatarHeightLowFudge 0.2" after changing to the region being tested.
> >>
> >> -- mb
> >>
> >> [1] For the technically inclined, the avatar is represented by a
> >>      rectangular shape. In the simulator, this shape uses physics to
> >>      rest on the terrain. The height of the avatar is divided by two
> >>      and added to this bottom location and sent to the viewer. The
> >>      viewer then divides its belief in the avatars height and subtracts
> >>      that from the location from the simulator to get the bottom of the
> >>      avatar. If that bottom is below where the viewer thinks the
> >>      terrain is, the viewer will move the avatar up a little to correct
> >>      the overlap. Given differences that can happen between the
> >>      simulator and viewer, they can start fighting each other with the
> >>      simulator placing the avatar with where it thinks it is and the
> >>      viewer making corrections depending on its calculation. This
> >>      fighting creates the jitter. Many attempts have been made to
> >>      reduce these height problems for all avatar heights and all
> >>      versions of the viewers but a perfect solution has not yet been
> >>      coded.
> >>
> >> On Sat, Feb 28, 2015 at 4:33 PM, Luisillo Contepomi
> >> <luisillo at contepomi.net> wrote:
> >>> Hi Ethan,
> >>>
> > I detect this problem on avatars size 3'10" / 46 Inch / 118cm. With
> > Singularity and Firestorm viewers.
> >>>
> >>>
> > What viewer are you using and the OpenSim Version and your avatar size?
> >>>
> > (I think the limit for this problem is < 120cm.)
> >>>
> >>>
> > I am using Firestorm (last release) on OpenSim 0.8.0.3 and I have not
> > this problem. My size is 4'5" / 53 Inch / 135cm. But with Singularity
> > and other viewers I have this problem.
> >>>
> >>>
> > Best regards,
> >>>
> > Luisillo
> >>>
> >>>
> > El 28/02/2015 a las 22:53, Ethan Grammatikidis escribió:
> >>>
> >>>>
> > Hi. When walking on sim terrain in a short avatar, I get really nasty
> > vibrations, making my view shake and everything. It's bad enough that I
> > can hardly walk around. This has been going on for over a year now, but
> > I just found it can be greatly reduced by a config change. I'd
> > appreciate any info on what config option it might be, and why the
> > default is so awful. (Would a change to that option make OpenSim more
> > likely to crash?)
> >>>
> >>>
> >>> _________________________________________________
> >>>
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> >>
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> >
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