Cineversity

Hi
I’ve setup a file where I have simple plane, on which I painted a “tear map”.
I put this map in the cloth tag’s tear map field, and once I hit play, the geometry that is inside of the tear area disappears…I only keep the outside.

https://www.dropbox.com/s/ks5j60gqwkf7uye/ClothTear_1.c4d?dl=0

What is weird is that I can see the point are there, and, if I select the plane object and press play, I see some weird geometry artifacts.  Is that due to my cloth tag settings?

Thanks!

Alex, are you sure you have had send the right file?

BTW, I guess you have seen this:
https://www.cineversity.com/vidplaylist/cloth_simulation/cloth_simulation_part_08

Perhaps Support:
https://www.maxon.net/en-us/support/how-can-we-help/

My best wishes.

Hmm, sorry, that was the wrong file.
I just tried again.  It seems to work ok as long as I don’t put the Cloth object, if I put it, I see the polygons disappearing.

Thanks for that link, exactly the kind of thing I want to do, but specifically having a problem with weight maps…
https://www.dropbox.com/s/o12cjs2ut0a5g3d/ClothTear_2.c4d?dl=0

Hi Alex,

Thanks for your file: The tear should be the lower value, and the reminder 100%. But the effect of missing polygons is untouched—I can see it. There was obviously a change, since the simulation itself is different in R17 to R18. So I checked even R12 as reference.
I’m not certain what other to say than, please contact the support. I really don’t know. If I dial the numbers down, the gap is gone, but it doesn’t break/tear anymore. To ask for dialing this in, animated, is perhaps too much to ask for or too “whatever”.
The problem is normally that the Weight values become multiplied with the value for the tear, so if the value is zero, then the “springs” inside the cloth are instantly broken, hence the tear, why the polygons dissapear is not clear to me and not in my power to fix. Support.
Cloth is a generator and this is calculated after generators normally, so there is a priority jump, and that might be the key that we can dial it to stay, then no tear, or no gap and tear. Not your concern nor your challenge, jsut to share a little bit the background.

Alternative—pre-version:

I have here something else, and please explore it, as my next file will build up on it.
It does not use a Weight map for the Tear, but for the Belt. The progress of the Belt-Weight is calculated with a falloff in XPresso. How far that goes with waving Fabric, I can’t tell. This was my Sunday, exploring this and I think that should be enough for this post. Perhaps you don’t like it, so I would like to see if it makes sense before I go further. Note that I just used all points to belt it to the Platonic object. Then I lower the belt with the weight map and the falloff. See the clip or the file.

One minute Clip (can be downloaded for better viewing experience):
https://www.amazon.com/clouddrive/share/3Hi7aB7pK4VFbggUYHraI0qNhGS8SaNdDJoj7de0Ojm?ref_=cd_ph_share_link_copy
File:
https://www.amazon.com/clouddrive/share/V3O2a2roDBKR5mYgnbcqjeB1ROIz8adkXR6gAvGW8tW?ref_=cd_ph_share_link_copy

Finally, the workaround:
Here I have prepared a set up like yours, but pre-fabricated the tear and used a belt to stitch it back, until the Weight map tells the belt differently.
The Falloff (XPresso) is set to source, and here I used the Sphere (the one that is set to Collide) and the points of the Sphere are the Falloff sources, each point!
So, when the cloth comes closer, the Falloff starts to change the Weight map and the belt function weakens.

File is here:
https://www.amazon.com/clouddrive/share/3WjHUjUDTZdRuJWesvLnfXKWfqJEeAu59YlJnBea2C?ref_=cd_ph_share_link_copy

My best wishes with the Project and the support.

Ha! Nice setup!  I really like it, the only issue I see is that having to work with topology like that could get a bit hard if the “cuts” are more complex shapes.  I was hoping to be able to use vertex maps so I could paint them rather than do polygon selection, but this will definitely help me a lot!  Thanks so much for the file, the recording and the detailed explanation, it makes a lot of sense, and is quite easy to follow. 
I’m going to start working with this setup tomorrow.

I did contact Maxon with my file.  Hopefully it will trigger some response.

Thanks again Sassi!  Great solution you found here!

Thanks, Alex, for the detailed feedback.

How about ignoring all of that and do something different. Not even tear apart things, but creating the “torn out part” with an alpha channel. So the same cloth is duplicated and flies even further, one time with the alpha channel and one time with an inverted alpha. Which would allow for so many more details, since it is a texture, instead of calculating perhaps a million polygons.

OK, enjoy your project.

Cheers

So you mean using transparency and various plane objects to drive the effect?  Combined with a cloth object?

Hi Alex,

The idea is to cache the first collision. With a second “fabric” the same collision happens , but in the moment it would tear, the collider move far away. This second fabric is cached while the first is not “enabled”.

In this way you get two objects, the part that got stopped by the collider and one that travels after a short “crash”.

In the Layer Manager you can disable the animation of the collider object. In the Cloth Tag you can enable or disable the “other” one for each caching.

Take any alpha (I used a gradient for this sketch) and with the colorizer, you can right mouse click on the Colorizer Gradient and use the “Invert” option.

[Please note that I’m in a few hours offline for two days. Thanks.]

All the best

File: [This is a rough sketch!]
https://www.amazon.com/clouddrive/share/Q8FUzXOxMsensC2D1dvyJxYLVS8UBKc2GT5rbMSBfPx?ref_=cd_ph_share_link_copy

That’s a great solution, but I’m a little bit confused…(no rush to explain of course).

So you cache the first “fabric”, then you disable the cache?  Maybe because I opened your file on my system I don’t see any cache stored on the cloth tag, even though I can see the effect working.

How do you move the sphere?  I was looking at your keyframes and they seem to stay at the same values, and the sphere doesn’t move?  Sorry if I’m missing something obvious!

And thanks again, really appreciate your guidance on all these solutions!

Alex,

I recorded a little clip, as I believe it is sometimes supportive to see things in action, rather than to walk through a bullet list.

Anyway
There are two ways (perhaps more) to make that happen, animating the sphere and disable it in the Layer Manager, or disable the Collider via enabled checked on and off as animation.

I could think of different set ups, e.g., using only one “fabric” (I avoid the term Cloth here for clarity) and animate the collider in any way. Copy that and use the copy to be slowed down in the moment of tearing. But please explore what works best for you. I think we talked about Point Cache (dis-able the Cloth Tag then.

Here is the clip, it is a little bit rough, sorry about that - again - you can download it:
https://www.amazon.com/clouddrive/share/TIuqVh963iRxQdHSCoLbQ8mokLk8CmKQ33deadWkEVk?ref_=cd_ph_share_link_copy

My best wishes for your project, I need to pack now.

Cheers

Hi Sassi

That clip made a lot of sense, and this technique is really great.  It allows me to use shaders to define the fracture, which is quite useful.

In the mean time, I heard back from Maxon support…They said the solution was to put the weight tag in the Stiffness parameter vs the Tear parameter…So it works fine now this way too.

Thanks again!

Thanks for the nice feedback, Alex.

Hey, that’s great that the Stiffness parameter works for you. I had not even the slightest clue that I should explore those. The learning never stops, thanks for posting. I’m glad the support is just that great!

My best wishes for your project