[osg-users] questions on simple skeletal animation for crowd simulation

[Bruno Fanini]

Hello osgUsers,

Within a osg-based crowd simulator I'm currently developing, I was trying to investigate a simple skeletal animation for a given set of agents.

I'm digging the animtkviewer.cpp example (osganimationviewer) and it looks like a good solution for this case.

In this context, I would just need a plain simple "walking" animation for my characters.

I've a set of PositionAttitudeTransforms nodes to control position & attitude of a single agent, so my questions are:

- is it possible to control the independent speed of the walking animation for a single agent? (i.e. another agent is walking faster, etc..)

- what about instancing 3d models? is it still possible with this approach somehow? (i.e. every p.a.t pointing to the same 3d model)

- what about the performance drop (estimate)?

- is there any example out there applied to crowd simulations or similar?

Thanks,

--
Bruno Fanini
http://BrunoFanini.co.nr

http://DevHelio.co.nr (Software Development)

http://www.facebook.com/DigitalDivadlo (Digital Art)

[Christian Buchner]

Are you sure your agents need to be full 3D models?

I've done something using perspective billboards, in the osgrvo2 sample in the osgRecipes repository maintained by Wang Rui. The billboards were rendered in Poser using a python script that rendered it out from many viewing angles.

The GPU can easily render 10000 agents with different walking speeds at interactive frame rates. The bottleneck is the agent simulation on the CPU. ;)

2012/11/17 Bruno Fanini <phoe...@gmail.com>

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[Jan Ciger]

Hello,

Back in the day I have done about 2000 walking skeletons for a demo using the osgCal plugin - i.e. no instancing, separate node each of them, software skinning (ok, skeletons don't have much skin :-p) they just shared some data. That was running at ~20fps on a GeForce4 back then. So it is certainly possible. Not sure how amenable the osgAnimation stuff is to that - to me it looked a bit unfinished and clunky when I worked with it last time.

The comment from Christian about billboards is certainly valid if you want to scale the simulation above some ~20k-50k characters - bellow that you probably will be able to drive fully articulated characters. With some clever LOD you can do even something like this:

http://archiveweb.epfl.ch/vrlab.epfl.ch/Movies/Movies_index.html (scroll down for the "Real-Time Navigating Crowds: Scalable Simulation and Rendering" video, the paper is here: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.90.3149&rep=rep1&type=pdf)

Of course, the CPU is the bottleneck, as Christian said - you need to push as much simulation as you can on the GPU.

Jan

[Bruno Fanini]

Hello Jan and Christian,

Thanks for your hints

The simulation has to run on medium-sized crowds (order of 1000-2000 agents) since we are planning to run on just a portion of a city, so actually theres no need for huge-sized crowds. At least not at the present times.

The architecture I'm developing should allow to separate completely the engine (collisions, social influences, etc) and let a separate FrontEnd to receive produced data, so it should be feasible both at CPU and GPU level.

Now I'm wondering where I can find some osgAnimation-based characters (apart from the classic "avatar.osg" in osg-data) or how can I generate a very basic walking character - I just need to control independently the walking speed - and have some tests. I've read something involving the Blender exporter: is this the only workflow (modeling) or I can find some basic animated agents around on the web that I can somehow convert to a osgAnimation-based setup?

Thanks,

[Sergey Polischuk]

Hi

 

You can use any .fbx model with skinned character, as osg can read those just fine. I think you should be able to find some of those in the web.

 

Cheers.

 

22.11.2012, 03:41, "Bruno Fanini" <phoe...@gmail.com>:

,

[Bruno Fanini]

With the same finder in animtkviewer:

struct AnimationManagerFinder : public osg::NodeVisitor {

    osg::ref_ptr<osgAnimation::BasicAnimationManager> AniMan;

    AnimationManagerFinder() : osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN) {}

    void apply(osg::Node& node) {

        if (AniMan.valid())

            return;

        if (node.getUpdateCallback()) {

            osgAnimation::AnimationManagerBase* b = dynamic_cast<osgAnimation::AnimationManagerBase*>(node.getUpdateCallback());

            if (b) {

                AniMan = new osgAnimation::BasicAnimationManager(*b);

                return;

            }

        }

        traverse(node);

    }

};

On Thu, Nov 29, 2012 at 6:46 PM, Bruno Fanini <phoe...@gmail.com> wrote:

Hello,

I'm testing some solutions and I have an exported animated model (it contains just one animation) that is correctly animated through the animationviewer player.

In my code I just want to play (in loop) that single animation forever, but nothing happens with these lines:

    _myModel = osgDB::readNodeFile("my-animated-model.osg");

     AnimationManagerFinder finder;

    _myModel->accept( finder );

if (finder.AniMan.valid()){

_aniMan = finder.AniMan.get();

_myModel->setUpdateCallback( _aniMan.get() );

const osgAnimation::AnimationList& animations = _aniMan->getAnimationList();

for (unsigned int i=0; i < animations.size(); ++i ){

_aniMan->playAnimation( animations[i] );

printf("Animation %d found\n",i);

animations[i]->setPlayMode( osgAnimation::Animation::LOOP );

}

}

I've did examine animtkviewer example and other, but I'm not able to figure out what's missing to play the animation... maybe somthing really stupid?

Thanks

[Bruno Fanini]

Hello,

I'm testing some solutions and I have an exported animated model (it contains just one animation) that is correctly animated through the animationviewer player.

In my code I just want to play (in loop) that single animation forever, but nothing happens with these lines:

    _myModel = osgDB::readNodeFile("my-animated-model.osg");

     AnimationManagerFinder finder;

    _myModel->accept( finder );

if (finder.AniMan.valid()){

_aniMan = finder.AniMan.get();

_myModel->setUpdateCallback( _aniMan.get() );

const osgAnimation::AnimationList& animations = _aniMan->getAnimationList();

for (unsigned int i=0; i < animations.size(); ++i ){

_aniMan->playAnimation( animations[i] );

printf("Animation %d found\n",i);

animations[i]->setPlayMode( osgAnimation::Animation::LOOP );

}

}

I've did examine animtkviewer example and other, but I'm not able to figure out what's missing to play the animation... maybe somthing really stupid?

Thanks

On Fri, Nov 23, 2012 at 11:08 AM, Sergey Polischuk <pol...@yandex.ru> wrote: