12 replies to this topic

[pramod]

Hi guys,
i am trying to simulate a bunch of helium balloon released and floating up towards the sky. Something like in this video: balloon_release. Right now i am not concentrating on the cloth simulation. First i am trying to get the motion of the balloons right. I tried this using rbd, but i am not able to get the right motion of the ballon in the air. I have attached my test file. It is a very basic setup. The problem with it is that the balloons are rotating a lot after they are released. I am not able to control their rotation. I tried rotation stiffness but it doesnt help.

Can someone help with this?? Am I in the right path or is there a better way to do this simulation??

thanks

Attached Files

•  BC_RND_HD_BALLON_V01_R02.hipnc   278.05K   60 downloads

Edited by pramod, 23 June 2012 - 11:12 AM.

[ehsan parizi]

if your balloons are as small as those balloons in your reference video, you won't need any kind of cloth sim!! unless you have huge balloons and you wanna be able to seem some detail!
anyway, why don't you just use a simple popnetwork instead of dops?! I think that'd make things easier! Is there any specific reason you're using DOPs?!

[pramod]

The cloth simulation is not for the balloon. It is for the cloth that is holding the balloons initially before they are released. Like seen in the video.
The reason behind using DOPs is that the balloons are going to be colliding with other objects that are in the scene.

[ehsan parizi]

pramod, on 23 June 2012 - 11:52 AM, said:

The cloth simulation is not for the balloon. It is for the cloth that is holding the balloons initially before they are released. Like seen in the video.
The reason behind using DOPs is that the balloons are going to be colliding with other objects that are in the scene.

Particles can collide too! I still think using particles is better, and you have control on your rotations!

[pramod]

ehsan parizi, on 23 June 2012 - 11:54 AM, said:

Particles can collide too! I still think using particles is better, and you have control on your rotations!

okay . . i will try doing it with particles. Havnt played around with particles much, will give it a try.
thanks.

[mantragora]

You can try adding RBDState DOP and damp Angular Velocity each frame a little.

Attached Files

•  fix_01.hipnc   290.63K   69 downloads

Edited by mantragora, 23 June 2012 - 01:06 PM.

[pramod]

mantragora, on 23 June 2012 - 01:06 PM, said:

You can try adding RBDState DOP and damp Angular Velocity each frame a little.

thanks will check it out. .

[old school]

The Drag DOP does pretty much the same thing as doing it manually in the RBD State DOP and it doesn't require any expressions either. The Scale Torque parameter takes the relative angular velocity and scales it back by the torque parameter. In this scene file, it just needs a value of 0.01 to get the balloons to settle down early on.

I also added $T to the offset in Y in the Wind DOP to add some more variation as the balloons drift upwards.

Nice simple fun file btw.

Attached Files

•  fix_02.hipnc   672.91K   95 downloads

[pramod]

old school, on 25 June 2012 - 01:48 PM, said:

The Drag DOP does pretty much the same thing as doing it manually in the RBD State DOP and it doesn't require any expressions either. The Scale Torque parameter takes the relative angular velocity and scales it back by the torque parameter. In this scene file, it just needs a value of 0.01 to get the balloons to settle down early on.

I also added $T to the offset in Y in the Wind DOP to add some more variation as the balloons drift upwards.

Nice simple fun file btw.

Awesome.. that seems to do the job. .simple and easy
cheers!!

[sanlin]

Hi,

you may try this instead... as i see that some of the balloons were really rotating crazily, it would be great that if we can control that particular balloon's motion.
we can further edit the balloon's rotation after it is being simulated. Just the one or few that you think you dont like its motion.
have a look at the file, i roughly replaced all of the balloons, but you can always pick the one that you want to change.
if you want to do it just for one balloon, take all the node inside the foreach node, except the each node inside foreach, and copy it just under the dop import node.. delete the connectivity and partition node. but you still need to check the name of the bad balloon though and rename them accordingly.

and you can even keyframe the balloon rotation as you see it appropriate.

hope this help. just a suggestion

Attached Files

•  try_01.hipnc   318.36K   67 downloads

[pramod]

hi all
Finally managed to complete the project. Thanks to all the help provided on this thread
It is my masters project. Pls check it out. Here is the vimeo link:
BalloonCity

One of the shots (shot3- floor shot) needs a lot more comp work. We didnt have time to fix it before the deadline. Hope we get time to fix it soon  

Edited by pramod, 09 September 2012 - 09:31 AM.

[nomad]

ha! Very creative!  )))
Thanks!