Help can tearablecloth be like egg membrane？

[superbad714]

Hello， I just bought Obi cloth for my project， great asset！
Now my project cloth simulated state is a little too elastic, is it possible to simulate the state of the egg membrane, which can be torn but will not have much elasticity?
Any help would be much appreciated.

[josemendez]

Hello， I just bought Obi cloth for my project， great asset！
Now my project cloth simulated state is a little too elastic, is it possible to simulate the state of the egg membrane, which can be torn but will not have much elasticity?
Any help would be much appreciated.

Hi!

Tearing and elasticity are completely independent of each other. You can make cloth arbitrarily stiff by using more distance constraint iterations/substeps (the manual contains a really in-depth explanation of how iterations and substeps affect simulation results). This doesn't have any effect on tearing, which is triggered using a force threshold.

kind regards,

[superbad714]

Hi!

Tearing and elasticity are completely independent of each other. You can make cloth arbitrarily stiff by using more distance constraint iterations/substeps (the manual contains a really in-depth explanation of how iterations and substeps affect simulation results). This doesn't have any effect on tearing, which is triggered using a force threshold.

kind regards,

Thanks for the reply, it is really helpful, here are my further questions:
1. Is it possible to make this torned  place like a completed hole, not just tiny triangles;
2. it teared mesh can be interactive(drag or click etc.)? no like just floating all around.
Any reply will be appreciated!

[josemendez]

Thanks for the reply, it is really helpful, here are my further questions:
1. Is it possible to make this torned  place like a completed hole, not just tiny triangles

Sure, just tear more triangles in the shape of a hole. However keep in mind you'll be restricted to tearing existing triangles in the mesh - just like in most other cloth simulators-, no new triangles will be generated since altering mesh topology that much in realtime is extremely expensive.

2. it teared mesh can be interactive(drag or click etc.)? no like just floating all around.
Any reply will be appreciated!

You can use the ObiParticlePicker/Dragger components to click and drag cloth particles around. You can also implement your own interaction using the particles API.

cheers!

[superbad714]

Sure, just tear more triangles in the shape of a hole. However keep in mind you'll be restricted to tearing existing triangles in the mesh - just like in most other cloth simulators-, no new triangles will be generated since altering mesh topology that much in realtime is extremely expensive.



You can use the ObiParticlePicker/Dragger components to click and drag cloth particles around. You can also implement your own interaction using the particles API.

cheers!

Thanks for the reply, its tearable cloth can be more like a soft body?
in drag tear cloth action, when I stop dragging, the cloth will bounce back, and the whole cloth mesh will behave like a water wave, why does the cloth behave like this and this can be modified?

[josemendez]

Thanks for the reply, its tearable cloth can be more like a soft body?
in drag tear cloth action, when I stop dragging, the cloth will bounce back, and the whole cloth mesh will behave like a water wave, why does the cloth behave like this and this can be modified?

Hi,

That's because by stretching the cloth you're building up potential energy that gets released in the form of a wave when you let go of it. All materials in the real world behave like this to an extent, depending on their elasticity/compliance.

First and foremost make sure that you're pulling the cloth with low enough force that the cloth is able to resist pulling. If you use an extremely large force cloth will stretch a lot, building up a large amount of potential energy.

To make the cloth less elastic, you can use more substeps and/or distance constraint iterations. The manual contains a very in-depth explanation of how the engine works internally and how substeps/iterations affect the results:
http://obi.virtualmethodstudio.com/manua...gence.html

You can also try using a larger "damping" parameter in the solver, which will make cloth dissipate energy faster. See: http://obi.virtualmethodstudio.com/manua...olver.html

kind regards,

[superbad714]

Hi,

That's because by stretching the cloth you're building up potential energy that gets released in the form of a wave when you let go of it. All materials in the real world behave like this to an extent, depending on their elasticity/compliance.

First and foremost make sure that you're pulling the cloth with low enough force that the cloth is able to resist pulling. If you use an extremely large force cloth will stretch a lot, building up a large amount of potential energy.

To make the cloth less elastic, you can use more substeps and/or distance constraint iterations. The manual contains a very in-depth explanation of how the engine works internally and how substeps/iterations affect the results:
http://obi.virtualmethodstudio.com/manua...gence.html

You can also try using a larger "damping" parameter in the solver, which will make cloth dissipate energy faster. See: http://obi.virtualmethodstudio.com/manua...olver.html

kind regards,

Appreciate your reply, it performed close to my thought and still has torn place particle issue.
can I get access to modify torn edge or particle？ or has another way to accomplish it.

[josemendez]

Appreciate your reply, it performed close to my thought and still has torn place particle issue.

Hi!

Not sure what you mean by "torn place particle issue", could you elaborate?

can I get access to modify torn edge or particle？ or has another way to accomplish it.

You can subscribe to cloth.OnClothTorn to get notified when a cloth edge is torn, and get information about which edge was torn, which particle was cloned as a result and the modified mesh faces.

kind regards,

[superbad714]

Hi!

Not sure what you mean by "torn place particle issue", could you elaborate?


You can subscribe to cloth.OnClothTorn to get notified when a cloth edge is torn, and get information about which edge was torn, which particle was cloned as a result, and the modified mesh faces.

kind regards,

Hi， when I finish the tear action, the torn place looks too many fragments, can access to modify it? Is it to make the edge more smooth, like a round hole.

https://i.postimg.cc/7YkkNNv0/obishot2.png
https://i.postimg.cc/gJyW9w8n/41afd269c9...900b2a.png

[josemendez]

Hi， when I finish the tear action, the torn place looks too many fragments, can access to modify it? Is it to make the edge more smooth, like a round hole.

https://i.postimg.cc/7YkkNNv0/obishot2.png
https://i.postimg.cc/gJyW9w8n/41afd269c9...900b2a.png

Other than using the automatic force-based tearing (which doesn't allow you to choose which edges are torn, these are selected based on a force threshold) you can call the cloth's Tear(StructuralConstraint edge) method manually on edges of your choice, which makes the shape  of the torn area entirely up to you.

Note that after calling Tear() one or more times, you must call cloth.UpdateDeformableTriangles(); to update the cloth's visual representation.