Approach for breaking a dynamic chain?
Posted: 10 March 2017 09:40 PM   [ Ignore ]  
Total Posts:  79
Joined  2012-04-04

I’m looking to create a simulation (or something) that looks like a chain breaking.  Basically I have four chains attached to an object in the middle of the frame stretching towards the camera and off to the sides of the frame (the foreground ends being off-camera).  At the appropriate time the chains break towards the middle and fall to the ground.

I can create a chain with cloned links suspended at the ends as dynamic bodies and smash a collider into it to break it in the middle.  The problem is the individual links stay intact as they fly apart and fall.  I was hoping there might be a way to add a Voronoi Fracture to my Cloner of links and tag that as a Dynamic Body so a few of the chain links could break apart, but then I’m losing the interactivity between the links.  Once the Cloner chain is under the Voronoi Fracture it behaves as a solid object.

Perhaps I’m missing a setting somewhere that would allow the chain to be flexible AND allow some of the links to break apart.

As I play around with this I’m now thinking I might get better results by faking this.  Given that I have four chains each with around 100 links a true dynamic simulation might be too slow and unpredictable. 

Maybe I could clone my length of links along two dynamic splines constrained at each end meeting with some static links in the middle with the Voronoi fracture tag applied.  As I make that explode I animate the objects constraining the ends of the splines and animate down the influence so they appear to detach in the middle, falling to the floor.

Thanks.

Profile
 
 
Posted: 10 March 2017 10:54 PM   [ Ignore ]   [ # 1 ]  
Moderator
Avatar
Total Posts:  4060
Joined  2011-03-03

Hi WSawn,

Please have a look into the file below:

Scene file
https://www.amazon.com/clouddrive/share/BAyN9y2lP3qmsnQGx7hyVsiIZEdLjVWhPlKXlf8AnfG?ref_=cd_ph_share_link_copy

The idea here is to place an Instance Object where the break should happen. In the moment it needs to break, the Instance Object becomes a new “Reference Object”. In this way the Dynamic Position stays the same as with the now replaced object. The Plain Effector, set to Modify Clones works with the MoGraph selection and with the Cloner Object set to Sort. So you can have one or several breaks in the chain. The old trick to set the parent object to invisible didn’t work, so perhaps place the objects for the Reference Object behind the camera, etc.

All the best

P.S.: Perhaps more to give you an other option, but it is certainly far from perfect.
https://www.amazon.com/clouddrive/share/fmyusqhcbFms65G4iEGl9BfvedqPkNNGIwODROzYl3a?ref_=cd_ph_share_link_copy
Not perfect, why posting it anyway? In the moment you cache the Cloth set up, the Cloth Cache Tool allows for a very nice manipulation of the result. Per point and frame or beyond. Save your Cache Result before you art-direct the results.

 Signature 

Dr. Sassi V. Sassmannshausen Ph.D.

Photography For C4D Artists: 200 Free Tutorials: Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

Profile
 
 
Posted: 11 March 2017 04:20 PM   [ Ignore ]   [ # 2 ]  
Total Posts:  79
Joined  2012-04-04

Hi Dr. Sassi:

Thanks again for the quick reply; I appreciate it.

Of your two solutions I think I’ll try upscaling the cloner with instance swapping version first.  As I originally wrote, I want to apply this treatment to four chains with around 100 links each.  I might be able to cheat the composition so the dynamics lift isn’t so heavy.

Regarding that setup, I understand how you’re swapping the instance of a whole torus with a fractured one, and (after some research) I understand how the Mograph Selection tag (with a Plain Effector) is specifying which clones will get swapped.  What I DON’T understand is how that fractured torus instance is being assigned to the clones selected by the Mograph Selector.  How does the Mograph Selector (or is it the Plain Effector) “know” to assign the Torus instance rather than the other (non-breaking) object under the Cloner?

Best.

Shawn

Profile
 
 
Posted: 11 March 2017 06:37 PM   [ Ignore ]   [ # 3 ]  
Moderator
Avatar
Total Posts:  4060
Joined  2011-03-03

Hi Shawn,

You’re welcome. Sorry if you had to research, I never know when I share too much or too little, everyones back-ground is different.

Please click on the Instance and then have a look into the Attribute Manager. There in the Object tab> Reference Object.

The “to be broken” element could be also an animated object. The visibility (size in the final rendering) is not to my knowledge, which could be also an edit/cut detail with an special animated detail shot. But I guess you have already a story-board in your head about.

IF the “soon to be broken” link can vaporize, then just place under a Torus an Explosion Deformer, animate it from 0-100% over a few frames for the motion blur of the burst, cache the whole set up and if needed, place broken pieces falling from the last position in an independent set up.

If the set up works, use the Cache options to keep things less CPU intensive.

I tried many “options” last night, but each “swap” action placed the fresh object to the initial position. The idea was that the Instance object stays, as it is practically just a container, and that the change in the reference keeps the Position and Rotation (+ Scale) information intact.

The Plain/Modify Clone set up enables any length of the chain and allows for a simple swap of the broken ones.

I haven’t looked into other options, as in Dynamic Spline or Spline IK/Joints to create the half-chains which would connect to the “to be broken” element. Perhaps worth a shot if the Dynamic file won’t work.
Another option would be in a Dynamic Connector set up. However I guess the suggested option is the simplest.

My best wishes for the project

 Signature 

Dr. Sassi V. Sassmannshausen Ph.D.

Photography For C4D Artists: 200 Free Tutorials: Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

Profile
 
 
Posted: 11 March 2017 07:05 PM   [ Ignore ]   [ # 4 ]  
Moderator
Avatar
Total Posts:  4060
Joined  2011-03-03

P.S.: I guess that might be the simplest set up, but again, maybe the link that breaks is not at all that visible (I really don’t know your camera settings), otherwise one could easily switch it off.

Scene file:
https://www.amazon.com/clouddrive/share/ucRkbVdUFz1UM7Je2DnkzGYtHzHRi0xeEeMZ3C5JeDP?ref_=cd_ph_share_link_copy

In the file below, the dynamic was just playing to get a feel for it were it could break.
With the first MoGraph Cache the frames 0-30 were cached. Link closed.
The Deformers opened then the link, and the second MoGraph Cache were then set up to calculate the frames from 31 to 72.

Scene file:
https://www.amazon.com/clouddrive/share/PasuW0i5r9dVMf8AVww7SGNIzuEjtfA1MbKROGQev0?ref_=cd_ph_share_link_copy

Enjoy your weekend

 Signature 

Dr. Sassi V. Sassmannshausen Ph.D.

Photography For C4D Artists: 200 Free Tutorials: Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

Profile
 
 
Posted: 11 March 2017 08:52 PM   [ Ignore ]   [ # 5 ]  
Total Posts:  79
Joined  2012-04-04

Hi:

No need to apologize for not explaining every single detail of your setup.  I do try to learn what I can on my own.  I’ve never used a Mograph selection, so I had to do a bit of research to understand its basic functionality.

I understand that the instance that “breaks” is first linked to a solid torus and then keyframed to link to the broken ring, which causes the chain to break.

There are two objects in the Cloner: the instance that “breaks” and a solid torus.  The cloner is set to make 6 clones.  We’ve used a Mograph Selection to isolate one of the clones.  What I don’t understand is why the “breaking instance” is the one connected to the Mograph Selection and not the other object in the Cloner, the solid Torus. 

By changing the order of the two cloned objects I can swap which ones end up breaking, and I could use this to create my chain.  I’d just like to understand how a particular clone is being assigned to the Mograph selection.

Thanks.

Shawn

Profile
 
 
Posted: 11 March 2017 09:05 PM   [ Ignore ]   [ # 6 ]  
Moderator
Avatar
Total Posts:  4060
Joined  2011-03-03

Hi Shawn,

It can be done either way, the clones in the selection (click on the tag to see what is selected) will given the Effector the information to modify this clone. IN the provided example all but the “instance” is selected.

There is no reason for one or the other to be preferred. If you click on the Selection Tag and then Attribute Manager> Tag> Invert (one time), the result will change completely. (Note that this will show no effect as long as the set up is cached.)

Just to be clear, if the selection had only the link-clone, it should be on the lower position. Just open the file below and let it play, then click from time to time on the Invert button. Wait until the play starts from fram zero to see the effect.

I hope that creates a good idea about the set up. Notice that the point color changes (located in the center of the torus, just a dot. yellow for selected and orange for not selected.


Scene file for the Invert “effect”:
https://www.amazon.com/clouddrive/share/qezqlU3aw1qCrwyx9vQ7YNKoD2MkBv50QQiuft826JU?ref_=cd_ph_share_link_copy

A short one minute clip “click-exploring” the scene:
https://www.amazon.com/clouddrive/share/ZCGiQPxshJ6MLq2fzwC6GLBwWPidHzsfOCrb0ELSMoH?ref_=cd_ph_share_link_copy

To explore this more, if you have more child objects under the Cloner (Sort or Blend), the Effector Setting “Modify Clone” will progressively go thought that. Either with the Slider itself or with the slider up and based on a Falloff.

Have a nice Sunday

 Signature 

Dr. Sassi V. Sassmannshausen Ph.D.

Photography For C4D Artists: 200 Free Tutorials: Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

Profile