New Kind of Physics Object

A few days ago Raigan (of metanet) was kind enough to introduce a new topic in the Fisix Engine forum.

Using the methods described in this paper:
http://graphics.ethz.ch/~brunoh/down...ions_SIG05.pdf

You can create an object out of particles but instead of having to use A LOT of constraints to keep the object together, this method just keeps them together without the need for a single constraints. And also, unlike constraints, the objects can have any shape and they will never lose it (unlike mass spring objects where particles can flip over to the other side)

So you can effortlessly create any shape, concave, convex, long and narrow, fat, everything works the same, and is always stable.. it's quite magical really :)

Here's a demo, it constructs a random shape using circles and wheels, and uses NO constraints
http://www.fisixengine.com/demos/demotest2.html

Oh, and yea, using this method you can also set a softness value which will make the objects more/less rigid

Soon enough you'll be able to play around with this in the Fisix Engine

That sounds intriguing... Maybe not so useful for stick figures, but still cool. How fast is it compared to using length constraints?

Also, the objects in your demo seem to be really rigid. Is it possible to make it softer?

Anyway, thanks for the link! :)

I haven't done any benchmarking yet so I'm not sure about the cpu constraints of this method

And yea, you can make it as soft or rigid as you'd like by altering a variable

Few questions I have:

Given the new variety of shapes this particle can handle, how will you handle for collisions?

Does this mean the end of some of your rigid body particles and/or maybe some optimizations to the engine overall?

Will you add on the ability for rigid body/ breakable constraints to constrain with two groups of these objects for ragdolls, lamps, trees, etc.?

I'd think this would go hand in hand with your blob demo (Fluid animations anyone?) and am quite anxious to see how this will come out. Good luck, Ozmic.

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Given the new variety of shapes this particle can handle, how will you handle for collisions?

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Well, collisions are still handled in the same way. The only thing that this method replaces is the way constraints are solved. You'd build an object out of the various particles of the engine and let them loose the same way you would with constraints... except here there are no constraints

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Does this mean the end of some of your rigid body particles and/or maybe some optimizations to the engine overall?

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Well, this was actually an unplanned (but very welcome) addition to the engine, but I do plan on adding the PolygonParticle still.
I should clarify though that this isn't a new particle, but more of a new method of constraining objects. In the engine, I added a ParticleBody class to handles this which extends the FisixObject class. You add and remove objects from it normally but here the objects always stay together

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Will you add on the ability for rigid body/ breakable constraints to constrain with two groups of these objects for ragdolls, lamps, trees, etc.?

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You can constrain any particle from one of these bodies to a particle in another body, so you can still build complex shapes with constraints

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I'd think this would go hand in hand with your blob demo (Fluid animations anyone?) and am quite anxious to see how this will come out. Good luck, Ozmic.

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Yea, I had the same ideas :) When I get a chance to play around with it I'll try to post more demos.
Thanks Opethrock, hope you're using (and enjoying) the engine.

Hey, remember this:
http://board.flashkit.com/board/showthread.php?t=658324

My first thread on Flashkit, never imagined it'd actually come this far

That old thread was an interesting read. It's funny, I started doing pretty much the same thing several months after. And apparently there was a guy who started a few months before you! But you're the one who has stuck with it. :)

Well, I did finish the engine for my game, but I haven't gotten around to doing much else with it yet.