Beam/Node interaction with Rigid body physics

This may have already been asked but I haven't seen anything in videos so far. Does it exist? Do you plan for it to exist? The thought sprung to mind on seeing LJF's picture of some rocks - rocks that you wouldn't really build out of beam/node structures but would probably want them to shift when you castrate your sedan going over the top of one. Other applications are practically endless, as you can imagine. Mundane examples include crushing stuff with boulders, carrying boxes in the back of a D15, etc.

 

Could you, as he asked, have rigid body boxes or stones in the bed of a D15 for example?

 

You can crash with them, so why can't you have them in the car?

 

You can crash with buildings and rocks in RoR too, but you can't have them in your truck... or move them at all.

 

If you have the same collision detection as for those scenery objects, but allow them to move, it would be the same and be possible. BUT, I don't know if there is any sort of dynamic/physics affected rigid body objects.

 

There is a screenshot somewhere of a car hitting some barrels and the barrels seem to be moving, so I'm sure you can place them in your van and carry them with you. So it can be done to other objects too.

 

But those are soft-body objects, I guess and they probably require a lot of processing power. I'm curious how many of those barrels can you have on a map and interact with them. Sometimes you really don't need them to be soft-body objects so I'm wondering if it's possible with rigid body physics with less processing power ?

 

I suppose if its not possible, you need only make a node/beam model for the rocks. In real life rocks do deform and resonate, maybe not to any noticeable extent but a lump of sandstone or schist will deform a small amount before cracks begin to propagate. So a simple soft body simulation should be fairly realistic if you make the beams extremely rigid. If what you make in terms of physics is basically a misshapen box, then it shouldn't be massively computationally expensive. At the simplest, I can see about 4 or 5 nodes per rock, and if a car averages at 300 nodes you could get roughly 60 rocks down for the price of a car in terms of computing power. its a baseless assumption, but that's a lot of rocks.

that said, rocks being rigid they might not call for flexbodies which also saves on computing power. you might find that my estimate is fairly conservative, or completely misguided.

 

The performance impact would be directly proportional to the number of beams and nodes the object is made up of + the overhead of having a beam/node object. You could have many more barrels than you could have cars.

The rocks you should easily be able to have several hundreds of, assuming they had very simple structures. Littered around the map, most of them would be sleeping, only awoken when you collide with them. Having several hundred inactive is very different to having several hundred in a landslide though, in which they are all awake, and making your computer catch fire.