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Submitted by Aras Pranckevicius, posted on December 31, 2004

Image Description, by Aras Pranckevicius

"Xplodar" is tiny demo of deformation simulation using Finite Element Modeling (FEM) technique. Done for similarly-named university course. Nothing fancy, just simulates some deforming model and lets you interact with it.

Basically, it's direct implementation of pretty standard stuff: tetrahedral elements, linear shape functions, Green's tensor, explicit integration. All this and more is nicely described in papers like Graphical Modeling and Animation of Brittle Fracture, some nice real-time tailored optimizations are in Real-Time Simulation of Deformation and Fracture of Stiff Materials.

You can see that the papers are on fracture, but Xplodar doesn't have one. Oh well, the eternal reason named "lack of time" :)

The demo can be downloaded from

Aras 'NeARAZ' Pranckevicius

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Archive Notice: This thread is old and no longer active. It is here for reference purposes. This thread was created on an older version of the flipcode forums, before the site closed in 2005. Please keep that in mind as you view this thread, as many of the topics and opinions may be outdated.

December 31, 2004, 01:32 PM

Looks very cool!

How are you doing the collision detection?


December 31, 2004, 03:04 PM

That's really cool, and from what I know, Tensor math isn't very easy. I had to learn the basics for my general relativity course.

Aras Pranckevicius

January 01, 2005, 05:20 AM

There's no self-collision, only collision with "walls". And that one is easy - just check with 6 planes of the cube, and use penalty method to apply forces to collided nodes.

Danny Chapman

January 01, 2005, 06:18 AM

That's pretty nice, and fun to play with.

Incidently, I did manage to turn the tip of one of the "structure2" legs inside out... (by being nasty and bashing it against a wall!)

Alex Herz

January 01, 2005, 10:20 AM

On my gf4 mx only the shadow of the object is visible :(

Aras Pranckevicius

January 01, 2005, 12:02 PM

Errr... drivers?

Ok, I've tried it only on some high-end (Geforce6800, Radeon9800) and some low-end (radeon 7000 - all ok; intel's integrated extreme gfx2 - no projected textures, hence buggy shadows).

Alex Herz

January 02, 2005, 07:19 AM

I'm running the latest 66.93 driver and Dx9.0c on an AMD 2600.



January 02, 2005, 10:02 AM

"Live for Speed" driving simulator has been using realistic deformation on the car tires since 2002, iirc. Looks very cool :)

Raigan Burns

January 02, 2005, 01:11 PM

i've also got a gf4mx, 9.0c and the latest drivers, and it's working perfectly here (very cool). p4 though, but i can't see how that would make a difference..


Alex Herz

January 03, 2005, 06:57 AM

I had another go..
it works with some of the models.

BoxCyl,csg,hinge and part don't work. The rest works fine..just didn't try em after the first I tried failed.

Fun thing to play with..
I always wanted to do a game with a proper physics sim..where objects deform/melt etc...

nice work.


Aras Pranckevicius

January 03, 2005, 10:55 AM


What if you run one of the buggy models, press F2 and if "vertex processing" (at the bottom) is not "software", switch it to the "software" one?

I know that some drivers of GF4MX claim to support vertex shaders, when in fact they don't, and once you start using dynamic geometry and vertex shaders, very bad things do happen. I forgot to include this "GF4MX workaround" test (i.e. force software VP on those) into Xplodar...

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