Re: texture shaking

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vsmsa (vsmsa++at++club-internet.fr)
Mon, 13 Sep 1999 09:07:53 +0100


Hi, thanks for your answer,

All my tiles are on (0,0), It's not possible for my customer to buy your LADBM tool.(So i prefer to have a Performer issues)
But I think, I made a part of it, when I move at each frame, all my tile around the observer who stays on (0,0).

I notice that the shaking is very important when i use texture detail.
Another information, When I had a single DB without the translation around (0,0), when I put a mobile in front of my observer, he was shaking.
Now it's good, may be it means that it's not a problem of precision, like gordon said, but only a mapping texture problem.

What do you think of it ?

Yoel.
    -----Message d'origine-----
    De : Gordon Tomlinson <gordon++at++paradigmsim.com>
    À : Angus Dorbie <dorbie++at++sgi.com>
    Cc : vsmsa <vsmsa++at++club-internet.fr>; info-vega <info-vega++at++paradigmsim.com>; info-performer <info-performer++at++sgi.com>
    Date : jeudi 9 septembre 1999 13:21
    Objet : Re: texture shaking
     
     
    Hi
    Are you using Vega's LADBM, this was created to solve the problems
    you get when you move a large distances from the Origin 0.0.0.

    The shaking of polygons and texture can normally be attributed
    precision problems when you are far from the 0.0.0

    as I said above LADBM solves this problem and give you access
    to Double floating point precision.
       

    If you are using LADBM and have these problems still, it would be
    best to log a support call, where were can follow up and get you a solution.
       

    regards

    Gordon
       

    Angus Dorbie wrote:

        There are some known and manageable issues with getting close very large
        'virtual' CLIP textures. These are handled through the manipulation of
        MIP level controls and/or texture coordinates with clip center position.
        In some ways the issues are similar to the specification of database
        geometry but may appear a little more arcane. Paradigm are experienced
        and expert at understanding these issues and if you are using Vega they
        may have solutions built in or be able to give you the Vega specific
        advice you require. If not then I'll be happy to advise on the general
        Performer issues.
        Cheers,Angus.

> vsmsa wrote:
>
> I use VEGA/Performer on IR 3 pipe.
> I notice texture shaking on my BDD.
>
> The first reason is that my BDD is too large, so I made tiles of
> 22000m x13000 m and I use dynamic object with the offset option of
> object panel on Lynx.
>
> My polygons always shake, but it's better.
> But if I choose a polygone with low coord., I notice that it's the
> texture which shakes.
> I read the manual pages about texture and detail texture, with a
> maximum of 11 levels. I respect this.
>
> Do you know some other reasons ?
>
> Yoel HALLAKOUN
> VSM sa

        --
        "One of the best-known folk theorems of software engineering is that
        60% to 75% of conventional software projects are either never
        completed or rejected by their intended users. If that range is
        anywhere near true (and I've never met a manager of any experience
        who disputes it) then more projects than not are being aimed at goals
        which are either (a) not realistically attainable, or (b) just plain
        wrong."
                         Eric S. Raymond - The Cathedral and The Bazaar

        For advanced 3D graphics Performer + OpenGL based examples and tutors:
        http://www.dorbie.com/

-- 

Regards

Gordon.

Gordon Tomlinson | Multigen - Paradigm Inc Vega Software Engineer | Suite 400, 14900 Landmark Blvd Email: gordon++at++paradigmsim.com | Dallas, Texas 75240, USA Tel: 972 960 2301 | Fax: 972 960 2303 ______________________________________________________________

'Smoke me a kipper skipper, I'll be back for breakfast' ______________________________________________________________

NOTE: All opinions here within this email are soley mine and DO NOT reflect those of MultiGen Paradigm or any other employee.

 
Hi, thanks for your answer,
 
All my tiles are on (0,0), It's not possible for my customer to buy your LADBM tool.(So i prefer to have a Performer issues)
But I think, I made a part of it, when I move at each frame, all my tile around the observer who stays on (0,0).
 
I notice that the shaking is very important when i use texture detail.
Another information, When I had a single DB without the translation around (0,0), when I put a mobile in front of my observer, he was shaking.
Now it's good, may be it means that it's not a problem of precision, like gordon said, but only a mapping texture problem.
 
What do you think of it ?
 
 
Yoel.
-----Message d'origine-----
De : Gordon Tomlinson <gordon++at++paradigmsim.com>
À : Angus Dorbie <dorbie++at++sgi.com>
Cc : vsmsa <vsmsa++at++club-internet.fr>; info-vega <info-vega++at++paradigmsim.com>; info-performer <info-performer++at++sgi.com>
Date : jeudi 9 septembre 1999 13:21
Objet : Re: texture shaking

Hi

Are you using Vega's LADBM, this was created to solve the problems
you get when you move a large distances from the Origin 0.0.0.

The shaking of polygons and texture can normally be attributed
precision problems when you are far from the 0.0.0

as I said above LADBM solves this problem and give you access
to Double floating point precision.
 

If you are using LADBM and have these problems still, it would be
best to log a support call, where were can follow up and get you a solution.
 

regards

Gordon
 

Angus Dorbie wrote:

There are some known and manageable issues with getting close very large
'virtual' CLIP textures. These are handled through the manipulation of
MIP level controls and/or texture coordinates with clip center position.
In some ways the issues are similar to the specification of database
geometry but may appear a little more arcane. Paradigm are experienced
and expert at understanding these issues and if you are using Vega they
may have solutions built in or be able to give you the Vega specific
advice you require. If not then I'll be happy to advise on the general
Performer issues.

Cheers,Angus.

> vsmsa wrote:
>
> I use VEGA/Performer on IR 3 pipe.
> I notice texture shaking on my BDD.
>
> The first reason is that my BDD is too large, so I made tiles of
> 22000m x13000 m and I use dynamic object with the offset option of
> object panel on Lynx.
>
> My polygons always shake, but it's better.
> But if I choose a polygone with low coord., I notice that it's the
> texture which shakes.
> I read the manual pages about texture and detail texture, with a
> maximum of 11 levels. I respect this.
>
> Do you know some other reasons ?
>
> Yoel HALLAKOUN
> VSM sa

--
"One of the best-known folk theorems of software engineering is that
60% to 75% of conventional software projects are either never
completed or rejected by their intended users. If that range is
anywhere near true (and I've never met a manager of any experience
who disputes it) then more projects than not are being aimed at goals
which are either (a) not realistically attainable, or (b) just plain
wrong."
                 Eric S. Raymond - The Cathedral and The Bazaar

For advanced 3D graphics Performer + OpenGL based examples and tutors:
http://www.dorbie.com/

-- 


Regards

Gordon.


Gordon Tomlinson              | Multigen - Paradigm  Inc
Vega Software Engineer        | Suite 400, 14900 Landmark Blvd
Email: gordon++at++paradigmsim.com | Dallas, Texas 75240, USA
Tel:    972 960 2301          | Fax:    972 960 2303  
______________________________________________________________

'Smoke me a kipper skipper, I'll be back for breakfast'         
______________________________________________________________

NOTE:
All opinions here within this email are soley mine and DO NOT 
reflect those of MultiGen Paradigm or any other employee.
 

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