Environtal Systems - as in Rain/Wind/Water and their impact

[KPNRG]

I'm a non-programmer - having programmed a couple decades ago on BASIC only

I hoped for some input which might be moderated between language appropriate to a programming newb and technical use which really communicates the ideas.

In part I hope for answers only to impact on my interest, but also that others - presumably of a more technical ability - might discuss and explore this idea as approproate and to their own.

The scenario is this:

An in game environmental system simulating wind and it's affect on such as flora and aqua - as in blowing leaves/trees, rain flurry, and water surfaces.

[/u]Some assumptions:[/u]

I think, this would most simply/easily be effected through something like a global switch - as in "storm=yes/no" the condition of which changes an object's animation appropriately - storm=no=normal tree animation/storm=yes=storm tree animation.

The negative impact of such a system is the utter lack of realistic behaviour in the reaction of such as a tree's movement to wind.

Like many things we/humans are able to distinguish 'unrealistic' behaviour from 'realistic' more often at a subconcious level - many times cinema CGI effects are discerned not because they are glaringly obvious, but because a suble 'tell' which we would recognise - such as in real natural phenomena - is lacking.

The questions - at length:

Imagining, however appropriate, some system whereby wind is modelled much like a physical object - and exerts appropriate pressure on the environment and visual change. A system simulating the nature of wind to gust, and eddie, and to, perhaps, subtly deform the visual cues of the game - such as flora/fauna bending in a steady wind, or suddenly impacted by a powerful gust. In addition, the impact likewise on liquid systems - to dynamically blow spray, cause waves and ripples.

Do such systems exist?
Is such a system feasible - and how so?
How would you see something like this being programmed?
How about putting this into place in Crystal Space?

Thoughts, explorations, anti-aircraft fire very much appreciated

[allpowerful32]

the switching of anims is fairly easy to do, as would the water, with an animated texture.  The problem lies with trying to simulate these things in realtime.  One tree with all of its leaves and branches simulated like this could take hours to simulate just a few minutes of waving in gusts.  A premade animation is the way to go.

[KPNRG]

Looking at a most realistic extreme - of simulating the complete flexibility of a branch and leaf - would seem to be  inappropriate to a realistic discussion in relation to a home PC.

But what about abstracting the 'system' to varying degrees - such as to treat the tree like a multisegmented/boned model - perhaps like a human model - and simulating and visualising flexibility only at a limited number of joints. Perhaps a tree is simulated with a joint between each of it's leaves and at various points along it's branches and trunk, or even that leaves as separate entities are abstracted entirely.

Imagine a single tree with 3 joints up it's trunk, 5 main branches each with a joint to the trunk, and each of those main branches with 5 of their own attached subsidiaries. But at this point no more - a total of 28 joints. Or even less at, for argument's sake, 7 in total.

Consider that in relation to a 'forest scene' with a kind of LOD also - where up to 10 trees only would be simulated to the above detail.

Ultimately, the system[/u] in place with a scalable degree of detail...

[allpowerful32]

The most advanced 64 bit cpus on the planet can simulate about 40-50 interacting objects in real time.  Just with trees, you've used most of that up.  Stick to a limited set of pre-made vertex animations until hardware become SIGNIFICANTLY faster.  Otherwise you are adding a lot of overhead for very little added visual realism.

[dingobloo]

actually offloading the swaying of trees to the GPU via a vertex shader is a very real possibility, and infact can be done in CS and has been by various projects, this along with a texture map that shows how much each part of the geometry should be effected by this wind, and you have quite a complex little system for dealing with wind.