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 Post subject: "Spring"
PostPosted: 09 Jul 2012, 11:13 
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Joined: 25 May 2012, 16:35
Posts: 67
Location: R&M
like to thank Hirazi
I want to publish little article that I was looking for a long time. This was taken from CGTalk, I hope I have not beaten for it :)
Ok here’s another area in XSI with lots of secrets that are not well known: springs.
In general there are 3 different kinds of springs in XSI and they all are good depending on what you are doing:



======== Spring Type 1: Rigid Body Spring ==========
located: Simulate > Rigid Body > Rigid Constraint > Spring
> These springs are bests for dynamics like robots or plates of lava or anywhere where you need bi-directional control like a necklace on a character or hanging telephone pole.
> You can also wire the springs into explosions and stuff like that to make chunks of debris stick together.



======== Spring Type 2: Evolve Op Spring ==========
> This is the newest Spring in XSI it was introduced in 4.2. The main purpose of this spring is for secondary animation that works over a renderfarm.
> located: (draw a linear curve for tail shape) > Animated > Skeleton > Create Tail.
> also located in Essentials + Advanced Biped Guide if you duplicate off the tail bone to create a tail or use a stomach.

This spring is very powerful having lots of options to blend between animation and simulation. It also has a bunch of different caching modes so you can do stuff like scrub backwards through your dynamics.

You can also apply this spring on single objects through scripting:

//--- start jscript here
var mysource = ActiveSceneRoot.AddActionSource("MySpringSource");
var a = CreatePrim("sphere", "NurbsSurface")
var b = CreatePrim("Sphere", "NurbsSurface")
Translate(a,10,10,10);
var opcoll = ApplySpringOp
(a+","+b, // simulated object, control object
40, // mass
5, // stiffness
3, // damping
mysource.FullName // spring simulation cache
);
InspectObj(opcoll(1));
//--- end script here

Make sure you experiment with Rest State and Initial State it’s on a bit of a diagonal by default.

======== Spring Type 3: Special Projects Spring ==========

A couple years ago Special Projects put a spring operator in XSI scripting to help solve some of the challenges at high end accounts. That spring operator is still in XSI and even has some new features not well known.

> located: Scripting (ApplyOp)


In general this spring carries bounce a lot more than a textbook spring algorithm. The only disadvantage is it’s live like a videogame so you need to plot if you are going to send it to a renderfarm.

The new features in 4.0 were:

> mute slider: Will blend between the spring being active and inactive. So you can blend out springy animation.

> init: When active drains all the energy out of the simulation. So if you have a very bouncy system you can blend the mute to 0, key init on for one frame and then when you blend back out you won’t have the carry over of all the bouncy energy.

//--- start jscript here
var a = CreatePrim("Cube", "MeshSurface")
var b = CreatePrim("Cube", "MeshSurface")
a.length = 3;
b.length = 3;
var op = ApplyOp("Spring",a +";"+b);
InspectObj(op);
//--- end script here



For those who are intrested in the spring operator and dont have a clue whats going on in the above post . u can easily test it out by doing the folowing

1. open script editor

2. type this
applyop "spring" ,,2

(the editor should be VB script by default but if its in jscript mode change it to vb)


3 select two objects and "Run" the script from the editor. The first object u selected will be "attached to the end of the spring" and the Spring will follow the second selected object.

4. to edit the spring properties= open the explorer and expand the "First selected object" to >kinematics>Global>pos>posx,y or z. you should see an "S" on the posistion values, Expand one more time and click that "S"Spring to get the spring properties

5. PLAY, key the "Second Selected Object" in a few positions and see what the values will do

================

or use Isners Quick little script
(Change editor to jscript and make sure immediate mode is off the run his script )
//--- start jscript here
var a = CreatePrim("Cube", "MeshSurface")
var b = CreatePrim("Cube", "MeshSurface")
a.length = 3;
b.length = 3;
var op = ApplyOp("Spring",a +";"+b);
InspectObj(op);
//--- end script here

just mentioned the other way of making them incase you want to start using the spring on different obects than cubes and to give a better understanding of whats going on when u make the spring


+ SPRING through " Simulate panel "

1. create 2 objects
2. Go to "Simulate panel"
3. select 1 object - "apply active rigid body "
4. select 2 object - "passive rigid body "
5. rigid constraint "Spring"

That's it! :-h \m/

_________________
http://www.youtube.com/watch?v=4q2wk0wiSC4 Wazzzaap Girls ! ;):)


Last edited by Boris on 15 Aug 2012, 10:09, edited 2 times in total.

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 Post subject: Re: "Spring"
PostPosted: 21 Jul 2012, 11:24 
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Joined: 17 Apr 2010, 12:41
Posts: 58
Thanks a lot for this list.
A few days ago I asked on the mailing list why isn't the "special projects spring" in the GUI. Eric Thivierge answered me that ICE Kine ('s spring?) and mt_Spring are newer setups that are better and more controllable. I haven't tested these yet, but they might be 2 other kinds of Springs you could add to your list...


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 Post subject: Re: "Spring"
PostPosted: 21 Jul 2012, 14:58 
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Joined: 25 May 2012, 16:35
Posts: 67
Location: R&M
grendizer wrote:
Thanks a lot for this list.
A few days ago I asked on the mailing list why isn't the "special projects spring" in the GUI. Eric Thivierge answered me that ICE Kine ('s spring?) and mt_Spring are newer setups that are better and more controllable. I haven't tested these yet, but they might be 2 other kinds of Springs you could add to your list...

Hello Man ! :) I'm sorry, I do not understand a little bit, if you mean "m_sprins" like this http://www.youtube.com/watch?v=O_XhNmN_C2g, I can not publish it to your list., It's addon and he is not mine. and about that "s spring" I don `t know anything. Good luck ! :-bd

_________________
http://www.youtube.com/watch?v=4q2wk0wiSC4 Wazzzaap Girls ! ;):)


Last edited by Boris on 24 Jul 2012, 21:37, edited 3 times in total.

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 Post subject: Re: "Spring"
PostPosted: 21 Jul 2012, 18:26 
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Joined: 15 Jun 2009, 00:57
Posts: 90
Boris wrote:
... I do not understand a little bit...

He was just saying you could add those to your list in the first post since you are documenting available options. :)


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 Post subject: Re: "Spring"
PostPosted: 21 Jul 2012, 19:04 
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Joined: 25 May 2012, 16:35
Posts: 67
Location: R&M
AceMastermind wrote:
Boris wrote:
... I do not understand a little bit...

He was just saying you could add those to your list in the first post since you are documenting available options. :)

now i understand :ymhug:

_________________
http://www.youtube.com/watch?v=4q2wk0wiSC4 Wazzzaap Girls ! ;):)


Last edited by Boris on 24 Jul 2012, 21:38, edited 1 time in total.

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 Post subject: Re: "Spring"
PostPosted: 22 Jul 2012, 20:10 
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Joined: 17 Apr 2010, 12:41
Posts: 58
Very interesting video about "mt_sprins". Anyone have tested the ICE kine spring?


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