View Full Version : Shockwave and bullet physics

Daniel Collin
03-17-2012, 03:21 AM

I have started to play around with bullet and the fracturing tools and got it all to work fine (like dropping a sphere on a fractured mesh) but what I want to do now is to do a "shockwave" that is supposed to blow out glas in a building.

I tried to add a null object and add various FX on it but it seems whatever I do bullet isn't affected at all by these settings.

Anyone has some other idea how I can do the effect without using nulls (or by using nulls with the correct FX applied to it)



03-17-2012, 06:27 AM

.... is to do a "shockwave" that is supposed to blow out glas in a building.

A "shockwave" is a job for VFX Postwork in AE, NUKE, Fusion not CG.

Daniel Collin
03-17-2012, 06:33 AM
A "shockwave" is a job for VFX Postwork in AE, NUKE, Fusion not CG.

Sorry I should have made this more clear but I mean the shockwave of actually blowing out the geometry (not the actually particles/effect itself)

03-17-2012, 08:35 PM
Maybe I don't understand what you are trying to do. But if I have it right...

Basically you just need some force to apply to the glass at a given frame and have it blow out. What force you use and how will depend on the effect you want. I have not used fracture at all. But in principle as far as dynamics are concerned you just need to have an object that has been fractured and then load it up into Layout as a solid piece, hit it with a force or some kind of collision object and it will fall apart etc.

One thing that can help is rather than use the fracture object for rendering the frames before the blowout, you can just have a solid glass object and swap this out on the frame the dynamics start with the fracture object.

So from here it is just a matter of getting it all set up so this works as you expect.

Does this help?

03-18-2012, 07:05 AM
Just an idea: use an animated black and white texture, e.g. a growing circle, applied to the Glue Strength. Or a growing sphere as a Kinematic object and adjust the Breaking Angle parameter accordingly. Then use a compositing app to reveal the fractured object over time.

03-18-2012, 02:11 PM
I don't think you can resize an object while using bullet. But you can just push an invisible sphere up through the floor to get the effect.



Or try a series of doughnuts if you want a more horizontal effect.

03-18-2012, 03:11 PM
I am pretty sure what he is saying is he does not want to see the actual shockwave.

A shockwave is the effect from, say a bomb. You don't neccessarily see this. It is a horizontal effect that pushes outward from a center, yes, but as far as windows are concerned, it just blows them out because it is just a force that pushes air our in all directions from a central point:


Just depends on where you want the center of the shockwave. If in the building it would blow things out from the inside.

So if I have this right, all you would need is the forces or collisions to simulate the effect with dynamics.

Daniel Collin
03-21-2012, 05:08 AM
Hi everyone and thanks for the replies.
I was able to get this working now.