soft body?

shlomi laszloshlomi laszlo Posts: 250
edited December 1969 in Carrara Discussion

1. how to stop soft body object get spiky and jump all over the place?

2. how to make a rubber ball that flattens on the ground, but doesn't loses air and roundness at the start in the air?

3. when a soft body object is used with another object that has bones only the start pose of the boned object is felt by the soft body one,
how to make the soft body object feel animated poses?

thanks shlomi

Comments

  • evilproducerevilproducer Posts: 9,040
    edited December 1969

    No idea about any of that, except to say that there must be parameters to adjust.

    As far as soft bodies interacting with rigged objects, this may help. It's geared more towards using soft body physics to work for clothes, but the principles on interacting with rigged figures should still apply:
    http://www.daz3d.com/forums/discussion/49954/

  • shlomi laszloshlomi laszlo Posts: 250
    edited December 1969

    got a morphed V4
    can't get a subset of it's polygons, in a morphed state, too copy to the clothing object.
    what should i do?

  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    1. how to stop soft body object get spiky and jump all over the place?

    2. how to make a rubber ball that flattens on the ground, but doesn't loses air and roundness at the start in the air?

    3. when a soft body object is used with another object that has bones only the start pose of the boned object is felt by the soft body one,
    how to make the soft body object feel animated poses?

    thanks shlomi

    You'll have to be a lot more specific about the problems you're having if you want some help. "Spiky soft body objects" can mean a lot of things, and we'd just be wasting our time trying to guess what your problem is.

    As far as rubber ball flattening, all I can tell you is my guess that maybe you're trying to use the soft body Volume/Pressure setting, which I recall is one of the Bullet settings that is not connected, and does nothing. Bullet is still in beta, and a lot of settings don't do anything.

    And I have no clue what you're referring to with your last issue. You'll need to post some more information on this stuff.

  • evilproducerevilproducer Posts: 9,040
    edited December 1969

    got a morphed V4
    can't get a subset of it's polygons, in a morphed state, too copy to the clothing object.
    what should i do?

    So you want to create a character with specific attributes in a V4 model, and then transfer those morphs to a clothing item that you have created for the V4?

    You could model in the Assembly room if you have a Pro version of Carrara. I'm not the best guy to describe it, because I create morphs so seldom, that every time I do it, it's like learning it all over again.

    diomede64 has been doing quite a bit of clothes creation and vertex modeling in Carrara. You could Private Message him or look for one of his threads where he discusses how to create morphs. He's very helpful and super nice.

  • DiomedeDiomede Posts: 15,088
    edited December 1969

    got a morphed V4
    can't get a subset of it's polygons, in a morphed state, too copy to the clothing object.
    what should i do?

    Hi, hope we can help. Like Joe, I'm not sure I know what you are trying to do, but here are some possibilities.

    - If you have a morphed V4, and an unmorphed clothing article, and you want to have an automatic way to move the morphs from the figure V4 to the clothing item, then you can use a utility. In Poser, this can be done with Wardrobe Wizard by converting the clothing item from V4 to V4 and choosing all of the morphs. I think Daz Studio's transfer utility will also do it, but I'm not sure because I don't use it for that purpose.

    - If you have a morphed V4 and are trying to get an editable mesh, you can export and reimport the V4 as an obj file. You can choose the options to make a mesh from each bodypart group if that will be helpful.

    - If you have a morphed V4, and are making your own clothing item to fit the morphed V4, then you can use Carrara's modeling in the assemble room to make the cloth item fit, export it to Daz Studio, and then use the transfer utility to make a conforming clothing item. However, current versions of Studio will likely ask you to convert V4 to triax before allowing you to do the transfer.

  • DiomedeDiomede Posts: 15,088
    edited March 2015

    Here are tutorial links from Carrara Café on the transfer utility. They might help.
    http://carraracafe.com/articles/creating-cloths-for-poser/

    EDIT - here is an older link from Daz on using Wardrobe Wizard for full body morphs from Victora (3!) to cloth mesh.
    http://docs.daz3d.com/doku.php/artzone/pub/tutorials/poser/poser-models01

    I can't link to it, but if you don't have a version of Poser, you can get a stand-alone version of Wardrobe Wizard from Phil Cooke. Do a search for wardrobe wizard and PhilC.

    Again, wardrobe wizard is not required if you can use Daz Studio's transfer utility.

    Post edited by Diomede on
  • shlomi laszloshlomi laszlo Posts: 250
    edited March 2015

    1. how to stop soft body object get spiky and jump all over the place?

    2. how to make a rubber ball that flattens on the ground, but doesn't loses air and roundness at the start in the air?

    3. when a soft body object is used with another object that has bones only the start pose of the boned object is felt by the soft body one,
    how to make the soft body object feel animated poses?

    thanks shlomi

    You'll have to be a lot more specific about the problems you're having if you want some help. "Spiky soft body objects" can mean a lot of things, and we'd just be wasting our time trying to guess what your problem is.

    As far as rubber ball flattening, all I can tell you is my guess that maybe you're trying to use the soft body Volume/Pressure setting, which I recall is one of the Bullet settings that is not connected, and does nothing. Bullet is still in beta, and a lot of settings don't do anything.

    And I have no clue what you're referring to with your last issue. You'll need to post some more information on this stuff.


    spiky & all over the place means:
    that i don't get a smooth flowing folds of cloth.
    what i get looks like each vertex placed randomly,
    and moves randomly from frame to frame.
    or to have a another look:
    spiky also means it looks like
    a terrain that scaled very large in the z scale,
    so the slopes are very steep.

    Post edited by shlomi laszlo on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969


    spiky & all over the place means:
    that i don't get a smooth flowing folds of cloth.
    what i get looks like each vertex placed randomly,
    and moves randomly from frame to frame.
    or to have a another look:
    spiky also means it looks like
    a terrain that scaled very large in the z scale,
    so the slopes are very steep.

    Well, the quality of the response you'll get is the same as the quality of the question :) :) :)

    It could be many things, but since you're not being clear or specific on the problem, just giving a short summary (no settings, procedures, etc.), we can only guess.

    My first guess is that you are setting a collision distance that is much too large. Try starting with it set at 10%.

  • Hermit CrabHermit Crab Posts: 839
    edited December 1969

    Hi Shlomi,

    Perhaps the spiky effect is being caused by the vertices of your mesh or meshes being too close together. Sometimes when I carried out soft-body simulations where a cloth mesh collided with an object, the simulation exploded - or the objects became spiky. The cause (in my case) was that the meshes were too dense.

    If your cloth mesh has only a few polygons and consists of very large faces then it could fold and bend into a shape like a (hanging) terrain - depending on the bending and stiffness settings - but I don't think that is what you've described.

    Creating a clothing mesh for soft-body simulations takes a bit of trial and error both with the mesh and with the physics settings. If you are using clothing which you bought, then the mesh may have a poly count which is too high. As this collides with a high-poly figure, you could get spikes (or an 'explosion')

    In your third question, you are asking why a soft body cloth can be draped over a rigged character successfully but when the character moves the cloth doesn't collide any more?

    That is the problem that disappoints so many of us with soft-body physics in Carrara. The thread which Evilproducer pointed to shows a long discussion of ways to overcome this problem. There has been some success in building a soft-body shell around parts of figures which clothing can collide against but the final settings to get this working perfectly are difficult to arrive at.

    Perhaps this is what you've been doing and is the reason you want to extract parts of the V4 figure? If so, I can only suggest that you look at what Jonstark and others have done in that long, long thread.

  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited March 2015

    Creating a clothing mesh for soft-body simulations takes a bit of trial and error both with the mesh and with the physics settings. If you are using clothing which you bought, then the mesh may have a poly count which is too high. As this collides with a high-poly figure, you could get spikes (or an 'explosion').

    I don't think the core issue of what you're describing is the mesh being too dense, it's that the collision distance/margin settings are too high for the dense mesh, as I was describing.

    What happens if the collision distance is too large for the given mesh, as soon as the sim starts it attempts to push each vertex in the dense mesh apart so that it is greater than the collision distance. This results in a "spiky" looking mesh. The other telltale of something like this is that the mesh itself suddenly increases in overall size.

    I don't recall ever having a mesh that is "too dense". In fact, Bullet seems to enjoy a very dense mesh, especially if it is very clean and uniform mesh. I tend to use dense subdivision meshes for my cloth because it looks and responds so well.

    On the other hand, a spikey mesh could be the result of other collision problems. But without more information on the settings and mesh used it's just guessing.

    Post edited by JoeMamma2000 on
  • Hermit CrabHermit Crab Posts: 839
    edited December 1969

    Hi Joe,

    Yes I get the point you're making and can't disagree. My understanding of all of this is based largely on observation of what happens in many trial simulations.

    When it comes to collision distance, I tend to switch in my mind between thinking of the distance between two objects which are about to meet one another (such as a cloth and a sphere) and the distance between vertices within an object. In other words, I'm vague about what I'm really doing as I change collision settings.

    Carrara gives us a slider for Collision Margin in the soft-body modifier and also gives a Collision Distance slider in the physics tab of the Scene settings. Since I don't have any strict definition of these settings, I can only experiment and try to see what difference each of them makes.

    I'll take on board your comment about Bullet Physics liking a lot of vertices to work with. (In fact I tried a very high-poly sphere colliding with a high-poly cloth and the results were very good indeed).

    I suppose the mesh-density / collision-distance relationship is affected by the size of a given object within a scene. Since collision distance is a measureable size, it stands to reason that if an object is scaled down to the point where its vertices are closer together than the collision distance, then the mesh could be thought of as being too dense whether it is high or low poly .

    Please be assured I'm not arguing here. Just trying to get my head round the whole thing! Above all I hope the OP isn't getting left out!

  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited March 2015

    I suppose the mesh-density / collision-distance relationship is affected by the size of a given object within a scene. Since collision distance is a measureable size, it stands to reason that if an object is scaled down to the point where its vertices are closer together than the collision distance, then the mesh could be thought of as being too dense whether it is high or low poly .

    The collision distance is a percentage number, and the percentage refers to a percent of the standard scene distance in a Carrara scene. I explained this in a tutorial I did long ago. You can determine that for yourself if you want.

    Take a cube as a collision object, then add a mesh plane as a cloth object, but make it smaller than a face of the cube. Set your collision distance at 100% and drop the cloth on the cube. You can measure how far the cloth stays from the face of the cube. An easy way to measure is to drop another cube in the scene and scale it down until it barely fits in between the cloth and the cube, then just read the dimension of that cube in the Z axis and voila, you have the exact collision distance. Then you'll see that that distance is a certain percentage of the standard scene distance, and that will pretty well match your collision distance/margin setting.

    You can also experiment with whether the collision distance affects the distance between vertices in a cloth object. It's really very simple. Once you've figured the distance percentage from the exercise above, you'll know what the real collision distance is. So make a mesh with vertices that are closer than that distance, do a sim, and see what happens. If the cloth expands or gets spiky, then you know it's affecting the vertices.

    Post edited by JoeMamma2000 on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    And the reason why there are two settings, one in the Scene settings and one in each cloth object, is so you can override the collision distance, if you want, for an individual cloth object instead of using the global scene setting.

  • Hermit CrabHermit Crab Posts: 839
    edited December 1969

    Hi Joe,

    Between writing my last post and seeing your reply a moment ago it did dawn on me that the collision distance - which I referred to as 'size' - is actually a percentage value and therefore there was a flaw in my understanding and in what I was saying.

    But it was thanks to your comments that I think I've come to understand this a little better. The empirical approach I've been taking isn't always the most reliable!

    Thanks for the clarity of your explanations.

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