[Opensim-users] Opensim Performance

[Dr Ramesh Ramloll]

Thanks Dahlia :)

On Fri, Dec 5, 2014 at 4:05 PM, Dahlia Trimble <dahliatrimble at gmail.com>
wrote:

> A lot depends on where the "physical" (moving, rigid objects or avatars)
> are relative to the static (non-movable) non-phantom objects. Collision
> testing can be a significant part of simulation load. It generally happens
> in multiple phases: a "broad phase" where any moving objects' sizes and
> positions are compared to other objects to see if they are close enough to
> warrant more precise testing, and a "narrow phase" where any potentially
> colliding surfaces are tested. If your scene is set up so that you have
> many complex collidable (non-phantom) static objects but all of your
> avatars are not near them then collision testing load should be fairly low.
> However if they are all standing on colidable objects made of hundreds of
> small prims then collision testing load will be much higher. Some prims
> and/or mesh models can have thousands of triangles which could each be
> subject to collision testing.
>
> In general if you have very complex objects it's probably better to make
> them phantom and superimpose a simpler, invisible shape which can be used
> for collisions. The mesh uploader in most viewers offers an optional
> "physics mesh" which could be used for this purpose as well. However, if
> simulation CPU load is not an issue for you then you could probably get
> away with ignoring such optimizations although considering how content is
> often repurposed it could be considered a best practice to use them.
>
> On Fri, Dec 5, 2014 at 12:16 PM, Dr Ramesh Ramloll <r.ramloll at gmail.com>
> wrote:
>
>> Hello there,
>> As I was reading about opensim performance on the opensimulator.org
>> site, I came across these two recommendations
>>
>>    - Make as many objects phantom as possible. Phantom objects do not
>>    need to be tested for collisions with avatars and other objects, reducing
>>    physics frame time and increasing performance.
>>    - Make as few objects subject to physics (e.g. falling under gravity,
>>    movable by other avatars) as possible. Physics objects need a lot more
>>    collision testing than ordinary non-phantom objects.
>>
>>
>> I understand these appear fairly logical. I am curious though, are these
>> differences really going to make perceptible improvements in user
>> experiences? Are there any metrics that would say help us know when to
>> start converting unnecessarily physical objects to phantom?
>> Thanks
>> Ramesh
>> --
>> 'Consider how the lilies grow. They do not labor or spin.'
>> *Rameshsharma Ramloll* PhD, CEO CTO DeepSemaphore LLC, Affiliate *Research
>> Associate Professor*, Idaho State University, Pocatello, ID 83209 Tel:
>> 208-240-0040
>> LinkedIn <http://www.linkedin.com/in/rameshramloll>, DeepSemaphore LLC
>> <http://www.deepsemaphore.com>, RezMela <http://www.rezmela.com>, Google+
>> profile <https://plus.google.com/103652369558830540272/about>
>>
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>>
>
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-- 
'Consider how the lilies grow. They do not labor or spin.'
*Rameshsharma Ramloll* PhD, CEO CTO DeepSemaphore LLC, Affiliate *Research
Associate Professor*, Idaho State University, Pocatello, ID 83209 Tel:
208-240-0040
LinkedIn <http://www.linkedin.com/in/rameshramloll>, DeepSemaphore LLC
<http://www.deepsemaphore.com>, RezMela <http://www.rezmela.com>, Google+
profile <https://plus.google.com/103652369558830540272/about>
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