How constraints Z position in 3D world

[Zavhoz]

Hi! How constraints Z position in 3D world for soft body? If switch Mode in solver to 2D, then all meshes is broken.

[josemendez]

Hi! How constraints Z position in 3D world for soft body? If switch Mode in solver to 2D, then all meshes is broken.

2D mode does exactly this: it "freezes" the z coordinate of all particle positions.

Disclaimer: it does not project the z coordinate to zero. It simply ensures the z coordinate is not modified by the simulation.

Can you share more info about your issue? We've been unable to reproduce any weird behavior in 2D mode.

[Zavhoz]

2D mode does exactly this: it "freezes" the z coordinate of all particle positions.

Disclaimer: it does not project the z coordinate to zero. It simply ensures the z coordinate is not modified by the simulation.

Can you share more info about your issue? We've been unable to reproduce any weird behavior in 2D mode.

3D mode:

  3dmode.jpg (Size: 28.6 KB / Downloads: 57)

2D mode:

  2dmode.jpg (Size: 27.82 KB / Downloads: 57)

[josemendez]

3D mode:


2D mode:

I think you misunderstood the basic concept behind softbodies: softbodies are composed of multiple particles. The global rotation of the softbody is a result of each individual particle's rotation, plus the constraints that hold them together. So in a sense, the object does not have an angular/linear velocity of its own, nor does it have a position/orientation.

If you use a full 3D mesh for the softbody, and then try to constraint its individual particles to 2D, it won't work, because each particle needs to be able to rotate in 3D even if the entire softbody seems to rotate in 2D only. For it to work as you expect you would have to constraint the position/orientation of the object as a whole, but it does not have one, so you cannot do that.

Use a flat 2D mesh for the simulation, with a 3D one bound to it. You can use a full 3D mesh and skin it to the 2D simulation using the ObiParticleSkinner. It will work as you expect. See this video (I used a rectangular mesh, if you're doing a ball you should use a circular one, but you get the idea):

[hungseparate]

Is this solver set to 2D mode ?
I tried did something like this video, but it still not work !

If set to 2d model -> plastic sheet work as i wanted -> mimic 3d model not
set to 3d -> both work fine but cant constrain z position ?!

Im using version 5.6

[josemendez]

Is this solver set to 2D mode ?
I tried did something like this video, but it still not work !

If set to 2d model -> plastic sheet work as i wanted -> mimic 3d model not
set to 3d -> both work fine but cant constrain z position ?!

Im using version 5.6

Hi,

Yes, this solver is set to 2D mode. I had no issues replicating the setup in the video, by using a flat mesh and binding a 3d model to it.

Can you give more details? What problems have you encountered? What did not work well for you?

[hungseparate]

Hi,

Yes, this solver is set to 2D mode. I had no issues replicating the setup in the video, by using a flat mesh and binding a 3d model to it.

Can you give more details? What problems have you encountered? What did not work well for you?

Tks for you respond, look like its my mistake, i do it again in you demo scene and it working fine, may be i did some wrong setting !

[gesila77]

I think you misunderstood the basic concept behind softbodies: softbodies are composed of multiple particles. The global rotation of the softbody is a result of each individual particle's rotation, plus the constraints that hold them together. So in a sense, the object does not have an angular/linear velocity of its own, nor does it have a position/orientation.

Use a flat 2D mesh for the simulation, with a 3D one bound to it. You can use a full 3D mesh and skin it to the 2D simulation using the ObiParticleSkinner. It will work as you expect. See this video (I used a rectangular mesh, if you're doing a ball you should use a circular one, but you get the idea):

hi, i made a circular one but look weird in 2d mode. Did i do something wrong?

[josemendez]

hi, i made a circular one but look weird in 2d mode. Did i do something wrong?

With no info on what you did, it's hard to tell!

What are your blueprint settings? Where is the ObiSoftbodySkinner component placed? is it in the same transform as the softbody?

[gesila77]

With no info on what you did, it's hard to tell!

What are your blueprint settings? Where is the ObiSoftbodySkinner component placed? is it in the same transform as the softbody?

Yes, obi in 2d mode. here are some screenshots