View Full Version : Air Balloon Deformations

06-21-2009, 11:13 AM
Hi Guys,
I would appreciate some help with an anim that I have been asked to produce. I need to animate the deformation of a high altitude weather balloon as it rises from ground level up to very high altitude. It needs to start very stretched and thin and then expand into the normal recognisable rounded shape as it gets higher.

My question is, how should I approach this? Should I use bones or morphs? or even perhaps some kind of cloth dynamics...yikes!

I have experimented with bones in a circular array positioned one at the top and one at the bottom of the envelope, and was going to vary the rest length of them to make the top fill out quicker than the bottom, but I am not sure how to gang 8 bones together to alter the rest length of all of the bones with one operation. Should I persevere with this idea or is there a better way?

Many thanks in advance


06-21-2009, 11:24 AM
Morph it ?

06-21-2009, 11:32 AM
Howdy Dave.

I reckon that a series of morphs would maybe give you the quickest solution, while bones would possibly give you more control...

Or, there is the option of using both together.

To get keyframes onto the bones quickly, you can: Make sure that all of the bones have a keyframe at frame 0, or 1; depending on your preference. From there, animate one bone as you see fit. After that, you can right-click the animated channel in the graph editor to copy the channel. From there, you can paste this envelope information to all of the other bones that need it by the same process (right-clicking in the channel to paste to in the graph editor), and offset the motion manually afterwards.

For bone grouping, you could create a null - make this a child of the balloon, then create the bones you need, all as children of the null... not as children of each other. From this, you will get individual control of their scale or rest length without the animation information being carried directly downstream.

In fact, creating your grouping this way will give you the opportunity of adding keyframes to all of the bones in one hit, and adjusting them individually afterwards too.

I'm not the best person to ask for morph stuff, though I'm sure other folk will chime in with either info on morphs, or decent tutorials for it.

Hope that helps.


06-21-2009, 11:58 AM
Thanks for the quick reply Zapper1998 and Flakester :thumbsup:. I was thinking perhaps a combination of both morphs and bones would be the answer. I will have a go at creating an endomorph later tonight although I am not very good at using the taper/size tools on organic shapes ( they tend to go all wonky ), however I shall play more with bones and the graph editor for a while to see what I can do.
Thanks for the help

06-21-2009, 07:35 PM
You could do a clothfx simulation to deflate the balloon, then use dpkit's mdd pointer node to play that backwards.
I think though you'd need some morphs to have it inflate a little, with clothfx over the top to make it ripple realistically.

06-21-2009, 08:22 PM
You could setup your object with an array of free floating skelegons to control the outside of your object. Similar to a lattice in other programs. And as Dodgy said you could mix morphs into your animation. You could also look into adding normal displacement or motion modifiers on your bone to add some random motion, like noisy channel or oscillator.

06-22-2009, 04:54 AM
Heres a couple of similar tests using an endomorph driven by a texture:

06-22-2009, 01:57 PM
Many thanks for all your replies. I am going with the Morph option mainly, plus a few bones to bend the overall shape as it's hit by different wind strengths.
Will let you know how it pans out..

Lastly I would just like to say how much I appreciate the helpful and friendly advise that comes from the Lightwave community, I am glad I went with this software when I decided to buy :thumbsup: