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Realistic Dynamic Fracturing with Bullet

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It is probably caused by angular velocity as it is transferred to new pieces, but their pivots are not the same as the original one.

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This is definitely a legendary thread! Hat off!

Still, I am not quite sure how would you render exactly such a sim? I mean, with bendable constrain network based on PIN constraints you get a bit too much "flickering" in the sim geo, so your low res prefractured pieces separate "slightly" from each another ( slightly meanining "enough to spot on a render"). I didnt notice this "problem" in the video Boris posted, but for example in the hip from Pavel is a big issue... Any thoughts?

 

edit: actually the scenes with the rebar have also this feature. It looks far better, when you see the iron rebbar, but it kinda is a bit too much for my liking.

Edited by xukca

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Hey Pavel, I tried to recreate this effect myself but ended up your setup pretty much 100%! The pieces are fracturing correctly however the non-shattered pieces seem to be behaving weirdly. If the pieces below fracture the non-shattered pieces stay where they are and don't fall... Could this be something to do with the constraints? Or maybe a naming issue on the pieces?

 

I've attached my file if you could take a quick look? Cheers

 

 

 

dynamic_fracturing_v2.hip

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I just added a check for distance on the constraints which seems to work... Was this the only thing I was missing? 

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My scene sort of working now, but there's a couple of issues. It would be great if someone could take a look at my file and see where i'm going wrong?! A few issues i'm having:

 

1. Some pieces are left isolated and hanging when they should fall since the pieces beneath them have broken

2. I'm struggling to get the fracture at the bottom of the concrete, it seems like the impact isn't propagating as much as in other videos?

3. Often pieces are shattered but then thrown in the wrong direction. It looks like the velocity needs to be transferred from the pieces from one frame earlier.. I briefly looked into keeping velocity from the previous frame and transferring this to the shattered pieces but it didn't work very well.

 

Hopefully someone can help!

dynamic_fracturing_v4.hip

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Awesome as always Pavel!!

 

Thanks for the *.hip!!

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HIP

hi, Pavel. thanks for sharing great examples.

but I can't understand why do you use "attribwrangle_to_mid" within constraint_control.

in my opinion, it just sets two points to the middle of them.

 

thanks.

 

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Thank you so much for the file. So many arised questions become slowly but surly a sense, respectively an answer

 

Thank you,

 

Follyx

Edited by Follyx

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by far this is one of the best threads i've ever come across i learned so much form it 

Cheers guys 

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Hi all!

New version of the setup for H14. The scene is much better organised and optimised.

There also some new features which makes this setup actually very useful.

 

 

Have Fun! 

 

Hi Pavel Pehlivanov,

 

This setup is really superb, thank you so much for sharing.

 

I have a small question.

I tried adding a external animated collision geometry on this setup. instead of using sop solver for generating the collision boxes.

but the autofracture_pieces sop solver is removing the collision geometry on frame 2 of the sim.

 

Any one who has knowledge of this setup please help me.

I tried different ways to add external geom but not yet successful.

 

Thanks in Advance, Looking forward for awesome odforce members comment

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I found a solution a bit of a hack though.

Instead of using a new Rbd packed object, i'm adding a collision geom in the same Rbd object and Everything works so smoothly.

 

Please let me know if anyone else given it a try in some other more clean way.

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question question;

I have a different problem, I simply scale the RBD packed with this Thanks to Tomas Slancik

matrix3 trn = primintrinsic(, "transform", @primnum);
matrix scalem = maketransform(, , {,,}, {,,}, scale, @P);
trn *= matrix3(scalem);
setprimintrinsic(, "transform", @primnum, trn);

 

but the collision shape is not updating, even though the guide geometry is scaling .

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