Video: Breaking Glass
Benito Buchheim is breaking a number of glass objects in slow motion in this video. The results are pretty good!
Benito writes:I experimented a bit with Blender’s Rigidbody function. The results are quite cool. I hope you like them too.
Everything rendered in Cycles with 300 Samples.
Some scenes rendered on SheepIt Renderfarm.
Very…solid. Quite rigid. I mean: very good! I really dig the light effects. Ooooo. Sparkles, many many sparkles.
Haha Thanks a lot. I like them too ;) :D
I have dealt with very high speed glass shatters in the past. To my eye the physics is quite wrong.
The bullet should start to deform the glass first, at the same time displacing it in the direction that the bullet travels. The glass would then shatter, with the shattering spreading very rapidly from around the point of impact. The glass fragments immediately around the points of impact would tend to follow the trajectory of the bullet. Those further out would merely drop straight down.
The stone ball dropping onto the glass ball is also incorrect, again with no deformation apparent. The glass fragments would again not fly out explosively with normal glass, and would tend to distribute themselves reasonably evenly in a circular pattern around the impact site.if, as shown here, the impact was central.
In fact both the wine glass and the glass ball behave as if they have been explosively broken from inside. One way that you could get anything like this behavior is if you used tempered glass. In that case the explosive fracture would be much more dramatic, with small, equal sized glass particles dispersing over a very wide radius.
In short, they’re very pretty. They just aren’t particularly accurate.
Yeah. I don’t really know whether that was my problem or a problem of Blender’s RigidBody Engine or Maybe there was something wrong with the prefractured Cell Fracture Shards. I think Blender thought they are inside one another. That results in this exploding effect. I think a feature in Blender would be really cool, which fractures the objects dynamically. You can see in my first example. Exactly when the bullet hits the glass, the side where the bullet goes through the second time, is broken too.
No one cares John
Hmmm. They look really sparkly!
But physics-wise the shattering and breakings are all wrong. The metal ball falling onto the glass ball is probably the oddest looking of the bunch. The metal ball just makes a tiny contact with the glass ball and the glass ball instantly breaks to pieces.
The wine glass after the ball also looks weird with the shards going through all directions equally. The general direction should be to the right following the bullet.
Things looks more like they exploded rather than just break and shatter by the impacts. These things might work well, in the bakground and without the slowmo that makes things obvious.
Technically there are lots of room of improvement but they still looks fun.
See my comment for jwrl. I know that there are many faults with the
physics. But I think it is a problem of the prefractured objects. Maybe I
can upload one source file so that you cann see the shards. Maybe the
are inside on another.
Well, from my limited knowledge. This kind of things is still quite a challenge in the world of computer simulations. In all the tutorials I read, the engines don’t really resolve this problems in physicaly based manner. Yours use prefractured objects so when viewed in scrutiny the flaws show themselves. There is no deforming and gradual fracturing of the objects which registers, even to the untrained eye, as strange.
This might be resolved by the developers in the future, I think.
Yes. Exactly what I mean. Thanks a lot.
It looks nice, but I agree about the physics though.
There’s a really great free course on Blendercookie:
http://cgcookie.com/blender/cgc-courses/breaking-objects-with-the-cell-fracture-add-on/
In the course a coffee cup is shattered by a bullet, and the result is quite realistic. The technices used would easily improve the physics in your examples.
Maybe I can upload one shot with these settings again. Let’s have a try.
Didn’t watch the clip yet, but the still image is showing the bullet still in the shell… minor thing, but still.. ☺
did you use any constraints between the shards ? I think that could help with the realism.there’s an addon to automatically add constraints between adjacent shards;http://bwide.wordpress.com/scripts/bullet-constraints-tools/
also there’s the rigid body fracture branch that’s very easy to work with, and makes some great results;http://graphicall.org/1031
Wow. Thank you very much. That is what I searched.
Hey folks, today I found a video of a piece of glass breaking, recorded at 10 million frames per second. That should settle any debates on the physics of this process :)
http://www.blendernation.com/2014/03/23/non-blender-glass-breaking-at-10000000-fps/
Enjoy!
Benito, I would be very happy to use one of these images for a cover to a prestigious scientific journal. Would it be possible to get your email and be in contact with you regarding this option?