LightWave - bullet dynamics and complex landscapes?

[today]

There's probably a simple answer to this, something I'm overlooking. I'm trying to use bullet to simulate an explosion in a complex landscape, so I have a keyframed expanding sphere as my 'kinematic body', and my ground as a 'static body'. Everything else is 'parts body'.

The simulation runs nice enough, but the problem is that everything starts falling apart from frame 1. Which is prior to the keyframed explosion actually colliding with anything.

My hunch is that it's defining the buildings interacting with the ground layer as a collision, and the preemptive dynamics are the result of that. How exactly would one avoid such a problem?

Seems like if I don't make the ground a static body, everything will just fall through it.

Doesn't really work to have the buildings floating either.

Some of the geometry does intersect the ground layer, and is in fact hidden below it. Should I boolean away anything below the ground layer?


I assume someone must have figured this one out. Any suggestions.

[today]

bump

[rustythe1]

set the objects to start "sleeping". objects do not calculate until they contact that way, however i think you may find an expanding sphear dose not work, i tried the same on an object and nothing happened!

[rustythe1]

also your ground should not be single sided, with bullet all your objects have to enclosed solids or water tight, otherwise strange things happen!

[today]

thanks I'm giving it another shot with a simpler landscape. Everything should be air tight, and the ground now has thickness.

Though for some reason some of my geometry simply vanishes after the first frame, not really sure what's going on there

[today]

Originally Posted by rustythe1

however i think you may find an expanding sphear dose not work, i tried the same on an object and nothing happened!

That is odd, I wonder why it does that

[today]

Is it specifically an expanding sphere that's the problem, or do dynamics fail to consider all keyframed kinematic objects?

[today]

Originally Posted by today

Though for some reason some of my geometry simply vanishes after the first frame, not really sure what's going on there

Ah. Nevermind, it's not vanishing.. in so much as it's being sucked through the ground and rapidly exploding. Well that makes sense

edit: think I've finally got a handle on this. Turns out it was interacting very oddly with the ground. I replaced the ground object with one with a few more subdivisions, and it seems to be working ok now.

[rustythe1]

i had problems with resizeing any object, if you do get it to work with an expanding object can you let us know how you did it, one would asume that is the best way to create big explosions so is something i would like to see work.

[today]

Originally Posted by rustythe1

i had problems with resizeing any object, if you do get it to work with an expanding object can you let us know how you did it, one would asume that is the best way to create big explosions so is something i would like to see work.

So far no luck with an expanding sphere. I have to assume it's either a bug, or some setting I'm missing.

[today]

http://youtu.be/XzcIB3bg4RE?hd=1



Since resizing didn't work, I resorted to rapidly moving a large sphere towards the camera.