anyone know to work with these goals??

[bigfatMELon]

There's a lot of lattitude within your description. Do you mean that you want the cylinder to move WITH the sphere (like a child) and react as a softbody or that you intend to collide the sphere with the cylinder? I'll assume the latter.

The thing to do, like any learning situation, is to break it down. On one hand you have the sphere. IS it a softbody or is it a rigid? If it's to be rigid then you should start with rigids (a good place to start with dynamics anyway) and learn what it means to be a rigid body. Having a good understanding of how rigid bodies work will make it much easier to fool around with soft bodies.

The second thing you should have some experience with before fooling around with soft bodies is particles. Why? Because that's what soft bodies are made out of and all of their controls ARE particle controls. If you understand how goals work with a simplified particle simulation, then you'll have much less trouble wrapping your head around soft bodies.

Above all, you must recognize that a "go here, do this, now teak that" answer will do you almost no good in the long run. Soft bodies, being the particle simulations that they are, require patience and willingness to test, observe, discover and retest. There are no magic settings, just generalized rules of thumb.

Having said that, keep these things in mind:


for objects to react to one another, each must be either a rigid body, a softbody or a particle with collisions enabled.
when you make a soft body, two objects result: a new surface that gets it's CV/vert positions from particles and the particle object that drives them. All of the important controls are found on the particle node.
a tiny amount of reduction on the Conserve field goes a VERY long way towards reigning behaviors in. Big reductions will make your behavior look dead.
each particle node has attrs for goal weights. The higher this setting goes, the longer it will take for a particle to arrive at it's goal position after either the goal or the particle has moved. In other words, the higher it goes the more gelatinous it becomes.
when previewing simulations, rigid, soft or otherwise, make sure your playback rate is set to "Free." All simulations are based on what has happened in the previous frame. If this previous frame gets dropped to maintain a specified playback rate, then the simulation goes foul.
in the Solvers menu there is an option for Edit Oversampling and Cache Settings. Generally speaking, good simulations of fast moving objects require that samples of the simulation be taken more than just once every frame. Turning Over Samples up will increase the accuracy of you playback.
at some point, every decent soft body sim needs to have two things done: 1) some level of alteration to the per-particle goal weights (you can paint these just like influence weights). 2) springs. Knowing springs is key to controlling softies.


-jl

[beatoperator]

cheers for the answer! :)

what I am trying to do is the first thing you said: "you want the cylinder to move WITH the sphere (like a child) and react as a softbody".

but, the problem is that very "dry" documentation and lack of tutorials on the internet which is related to soft bodies (in fact, I didn't find any tutorial).

that's why I post this question here...

thanx :)

[bigfatMELon]

There are, in fact, a number of tutorials at http://www.aw.sgi.com/ and www.highend3d.com that cover particles, rigids and softies. I wouldn't call it comprehensive material but it's a good start toward understanding.

Documenting simulation software is very difficult in written form because there are so many possibilities. The best learning material I've seen for this stuff is the video tapes from http://www.gnomon3d.com/.

-jl

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