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Author viewpoint animation wobles
Steve Smith

2006-11-19, 7:36 pm

I find (with both contact and cortona) that I get the wobles in fairly heavy
scenes when an animated view aproaches any object.
Even when collision is dissabled.
Has anyone any tricks for avoiding this ?

Thanks

Steve


simon

2006-11-19, 7:36 pm

by wobles do you mean changes in the direction of view?

haven't seem this before, how about an example.

Josip Almasi

2006-11-19, 7:36 pm

Steve Smith wrote:
> I find (with both contact and cortona) that I get the wobles in fairly heavy
> scenes when an animated view aproaches any object.
> Even when collision is dissabled.
> Has anyone any tricks for avoiding this ?


I'm not sure what you mean by 'wobles'.
Though there's a catch with huge worlds - float data type isn't enough
to allow good rendering. Like, you have 7 good digits, meaning you get
10 cm error on 500x500 km terrain.
Workaround is to use fixed viewpoint and animate the world.
(float is more 'dense' around zero)
Chris Thorne wrote some papers about...

Regards...
Steve Smith

2006-11-19, 7:36 pm

have a look at http://www.veps3d.co.uk/solarsystem/anim.wrl
the wobles start as you zoom towards earth surface

> by wobles do you mean changes in the direction of view?
>
> haven't seem this before, how about an example.
>



Steve Smith

2006-11-19, 7:36 pm

Well I am using a geographic coordinate system which uses 7 digits.
But I am seeing with scenes of no more than 5 digits.

"Josip Almasi" <joe@vrspace.org> wrote in message
news:ej2c8q$le$1@ss408.t-com.hr...
> Steve Smith wrote:
>
> I'm not sure what you mean by 'wobles'.
> Though there's a catch with huge worlds - float data type isn't enough to
> allow good rendering. Like, you have 7 good digits, meaning you get 10 cm
> error on 500x500 km terrain.
> Workaround is to use fixed viewpoint and animate the world.
> (float is more 'dense' around zero)
> Chris Thorne wrote some papers about...
>
> Regards...



simon

2006-11-19, 7:36 pm

yes, i can see the wobbles, looks to me like maybe multiple and
slightly different events going to the viewpoint.

for something a bit like this i've had happen to me, i added some code
to fork the route and print out the events to the console, can be very
informative.

simon

Holger Grahn

2006-11-19, 7:36 pm

Hi Steve,

The wooble effect looks like floating point jitter.
As Josip says try to adapt the coordinate system or shift it dynamically
during navigation.

Greetings
Holger


"Steve Smith" <gostudio@btinternet.com> schrieb im Newsbeitrag
news:Wvudnc9lx5lyWcnYRVnyvQ@bt.com...
> Well I am using a geographic coordinate system which uses 7 digits.
> But I am seeing with scenes of no more than 5 digits.
>
> "Josip Almasi" <joe@vrspace.org> wrote in message
> news:ej2c8q$le$1@ss408.t-com.hr...
>
>



Steve Smith

2006-11-19, 7:36 pm

Thanks Holger,

Is this something which could be resolved by tranlslating to X3D which has
double the digits ?

Steve

"Holger Grahn" <spam@x79.net> wrote in message
news:4rsd0mFsfldmU1@mid.uni-berlin.de...
> Hi Steve,
>
> The wooble effect looks like floating point jitter.
> As Josip says try to adapt the coordinate system or shift it dynamically
> during navigation.
>
> Greetings
> Holger
>
>
> "Steve Smith" <gostudio@btinternet.com> schrieb im Newsbeitrag
> news:Wvudnc9lx5lyWcnYRVnyvQ@bt.com...
>
>



Josip Almasi

2006-11-19, 7:36 pm

Steve Smith wrote:
> Well I am using a geographic coordinate system which uses 7 digits.
> But I am seeing with scenes of no more than 5 digits.


It doesn't really matter how many digits _you_ use; it's up to browser,
how many digits it uses to calculate what should be seen and what should
be hidden.

Regards...
Josip Almasi

2006-11-19, 7:36 pm

Steve Smith wrote:
> Thanks Holger,
>
> Is this something which could be resolved by tranlslating to X3D which has
> double the digits ?


Give it a try and let us know... maybe you should try with Xj3D, I
believe it uses double internally (j3d) so maybe you don't even need to
convert.

Regards...
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