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Animation with wind and hook ?

Posted: Thu Jun 16, 2011 10:20 am
by Lou
Hi !

I just follow a tutorial to create balloon with a rope. This rope is hooked. So when I duplicate balloon + rope and that I move the balloon, all the rope have the same root.

I would like to know if it is possible to animate this balloon with a field of wind and collision between them. And with the hook activated and then released ?

Thank you for your time and help if possible...

Posted: Thu Jun 30, 2011 8:22 pm
by simtron
Make balloons cloth bodies.
Invert gravity on balloons as they fly against gravity direction in the fields.
Turn on cloth collision->self collision.This will handle cloth colliding with itself.
Increase the bend value to 100+ so that the balloon wont collapse as if its empty.
For wind effects you need to add force field body of type wind and set it in direction.
For active collisions add collision to all the bodies which involve collision.

The rest is all about hooks force animation and stuff.
Try it and show me the result.I'm eager to see it :D

Posted: Thu Jun 30, 2011 10:52 pm
by Lou
thank you for you help !
So now my ballon fly up and have colision. But the wind does not affect them at all !!!?

I promise I put the render animation when this will be okay !

I will search why the wind does not affect balloon and why the balloon fly and the rope no follow...

Posted: Fri Jul 01, 2011 7:38 am
by simtron
Friend..."Let the force be with the wind" :wink:

Go into physics panel.Select your wind force body.In the properties of wind force body you will see an option called strength.This will alter the force.Test and choose the best value for it.For better effects you can animate this too!!!

If you hit i key on strength and change its value with time, your wind can also be animated.
For random noise in flow, you can add noise.If you want to animate random rotation of wind,hit I key and choose rotation on 3d view with wind obj selected, this will insert key frames for animation.In graph editor, you will find the animation key frame tween graph.You can go into rotation, choose some axis and add a noise modifier and tweak few settings.
(You can see modifier menu on the side panel.The modifier panel can be toggled to make visible via N key)

Posted: Fri Jul 01, 2011 7:41 am
by simtron
Happy to hear that there are women who use blender. :D

Posted: Fri Jul 01, 2011 8:42 am
by Lou
Hi :D Thank you !

Okay, I will try again tonight when I go home. Just a question, I create a extern wind force... Is it wrong ? Do I have to add the wind in the balloon to ?

Sorry, I see some mistake in my writting... (I am French, I will take care...).

Yes, for ma signature... I read a document from a Blender conference that says that only 2% percent of people that use Blender are girl.
I wonder myself why ? I think it is also because there are few girl in computer science study... But I do not know why again !? ^^
Maybe, I will be very pleased to work on Mango (if Ton wants...) to represent girl in a Blender open project.


Posted: Fri Jul 01, 2011 7:41 pm
by simtron
Force field are not particulate simulations like in real world.They just emulate the presence of force.You don't have to place a wind obj inside balloon necessarily.But you may try it.You can try it.I guess., nothing big will happen b'coz an internal disturbance in a body wont affect the body itself as a whole.

For example., it like having a fan installed on a ship to set off sails.No body will do that, but you can see the sails moving because of the wind.

I wish you best luck.May you get a chance in Mango project and make a solid mark in Blender history dear friend.

Posted: Sat Jul 02, 2011 11:15 am
by Lou
Just because I doubt... It is cloth or soft body ? Because you say cloth body... ? I will test now !

With a soft body, my balloon is link to my rope. That is good. But it only move up and down like is the wind does not affect him... Maybe because my rope is just a simple object. I try to make to it a soft body modifier also. But it is no more kooked... It is like a little rop that is floating everywhere but the balloon and the rope are still linked at a point...

If I use cloth body, the ballon goes up and it is no more linked to my balloon...

I continue my test...
But maybe we can animate this scène with hook in fact... maybe I habe to disable this, and make my balloon fly every where...
But I wanted to simulate there are always linked...
Or maybe, I have to animate by hand...

(I do not think of it before, but maybe it is very hard to be taken for the open project... because a lot of people wants to do this... ???)

Posted: Sat Jul 02, 2011 2:33 pm
by simtron
Soft body is like making the object out of jelly.It just moves about the place where it is placed.If you hit it with a rigid object with collision options, the soft body responds just like jelly.As soft bodies aren't affected by the wind in blender, you cant see it flying.

I get your problem.

As both entities are likely cloth type(balloon and rope) why dont you just join them together and move the rope via a hook???By this both balloon and rope will be together and you can control movement of the whole set up via a hook to the tip vertices of the rope.You have to choose the same vertex group under the pinning option in cloth bodies.This decides where your cloth can be manipulated.

As of materials they will remain intact even if you join them, but make sure that you have seperate mesh groups for balloon and rope so that you can handle these meshes individually.

Posted: Sun Jul 03, 2011 12:03 am
by Lou
So, a little video to show you.
The ballon in the top are cloth with collision, not linked to the rope that have colision too. It seems that wind that not affect them... And the rope that is around the balloon let them to not fly away...

The ballon in the bottom is joined with the rope. It seems that it is very affected by the wind. It is a little weird by the way... (upload is pending...)

Posted: Sun Jul 03, 2011 6:23 am
by simtron
Nice work.

As of bottom balloon it seems like its leaking air. ;)
It should be the ropes and that might have been tangling with the balloon or lack of strength.

Any ways, the render is good.Nice choice of colors.It looks just like the example in the 's tutorial right!

Posted: Sun Jul 03, 2011 9:35 am
by Lou
Yes it is this tutorial.
So maybe if I decrease the lenght of wind and make a rope more longer it will be good.
But I do know understand why the others balloon (in the top) are not affected by the wind...) I have a wind size that is all arround the balloon !
Hi !

Thank you for your help ! I have a lot of things to explore !

Posted: Sun Jul 03, 2011 9:56 am
by simtron
The size of force body doesn't matter.You need strength.Also reduce the mass of cloth.By default it should be 1kg which is highly unnatural for a child's balloon.

Posted: Sun Jul 03, 2011 10:39 am
by Lou
Ok. I will try it ! Thank !!!