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Thread: Bones deformation on flat large objects

  1. #1
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    Bones deformation on flat large objects

    Hi guys, I'm trying to deform an object like this, from flat to fold, it'll be an animation:

    Click image for larger version. 

Name:	bone_deform_01.jpg 
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ID:	133768

    I started with just a row of bones, then I tried to add two more to have more control over the whole mesh, but I'm not sure how to avoid that ugly deformation in the middle of the fold: I just need a nice round deformation, like if I was using the Bend tool with a small radius in modeler.
    I tried also with morph, but it needs many steps and I can't get a smooth transition.

    What's the best way to deform an object like this?

    The final object will probably be a subd poly mesh with some poly details, something coming from zbrush probably.

  2. #2
    Axes grinder- Dongle #99
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    Have you tried weight maps? I believe fewer bones w/weight maps would work better.

    The big trick is getting the gradient across the fold right.
    They only call it 'class warfare' when we fight back.
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  3. #3
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    You could use the Bend deformation tool, under the object Properties=>Deform tab. Sample scene attached.

    mTp
    Attached Files Attached Files

  4. #4
    skeptic lertola2's Avatar
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    Yes weight maps is a good way to do this. The attached scene shows a way this could be set up.

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Name:	book_cover.gif 
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  5. #5
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    Quote Originally Posted by jeric_synergy View Post
    Have you tried weight maps? I believe fewer bones w/weight maps would work better.

    The big trick is getting the gradient across the fold right.
    No luck with weight maps jeric, but I solved with mTp's trick.

    Quote Originally Posted by MonroePoteet View Post
    You could use the Bend deformation tool, under the object Properties=>Deform tab. Sample scene attached.

    mTp
    I totally forgot about the basic deformation tools in layout: this works perfect! Thanks mTp.

    I'm still curious how to achieve the same with bones, I'm sure that sooner or later I'll end uo in a situation that the Bend tool will not be enough.


    EDIT: I see now your reply lertola2, I'll try your scene also
    Last edited by S0nny; 07-22-2016 at 09:48 AM.

  6. #6
    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by S0nny View Post
    Hi guys, I'm trying to deform an object like this, from flat to fold, it'll be an animation:

    Click image for larger version. 

Name:	bone_deform_01.jpg 
Views:	92 
Size:	266.0 KB 
ID:	133768

    I started with just a row of bones, then I tried to add two more to have more control over the whole mesh, but I'm not sure how to avoid that ugly deformation in the middle of the fold: I just need a nice round deformation, like if I was using the Bend tool with a small radius in modeler.
    I tried also with morph, but it needs many steps and I can't get a smooth transition.

    What's the best way to deform an object like this?

    The final object will probably be a subd poly mesh with some poly details, something coming from zbrush probably.
    perhaps continues joined bones going the same direction as the bend direction, just in the middle ..not different bone directions and not on the sides, just split or make several bones in the joint, then select those in bone mode and rotate.

  7. #7
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    Ok, maybe it's me, but I guess I need to experiment more with bones setup.

    This is the movement with 3 weights:

    Click image for larger version. 

Name:	bones_01.gif 
Views:	57 
Size:	365.6 KB 
ID:	133777

    and this is the bend tool, which is perfect for what I need to do:

    Click image for larger version. 

Name:	bend_01.gif 
Views:	47 
Size:	307.1 KB 
ID:	133778

    I guess I'll stick with bend deformation for now, this is a 20cm thick soft foam material and bones have that organic behaviour which cause that compression on the mesh that I don't like.

  8. #8
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    Here's a bones setup which works well, IMO. The bone chain was created by slicing the object in half with Knife, selecting the points in the bottom center edge (select first two, then right-arrow to expand selection to limit), creating a curve with CTRL-p, use Setup=>Convert Skelegons, and deleting the curve. You could use one of the side edges to create the skelegons, but they need to be moved into the center to affect the entire width without falloff.

    In Layout, use Setup=>Add=>Convert Skelegons to create the bone chain. The animation is just selecting all the bones after the bottom flat part (in this case, Bone.002 through Bone.018) in Scene Editor, rotating them each 180/17 degrees so the summation of the 17 bones is 180 degrees, and clearing the Multiply Strength by Rest Length flag on all of them.

    In your bone setup, you might try clearing the Multiply Strength by Rest Length for each curvature bone if you haven't to see if your undesired deformation goes away.

    mTp
    Attached Files Attached Files
    Last edited by MonroePoteet; 07-22-2016 at 03:14 PM. Reason: Clear Multiply Strength by Rest Length

  9. #9
    Big fan of coffee raw-m's Avatar
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    Interesting thread! Thinking a stage further, if you had pages inbetween, what's a good approach to bolt the pages in place so they follow the displacement of the spine opening, so pages are evenly distributed from to back?

  10. #10
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    Quote Originally Posted by MonroePoteet View Post
    In your bone setup, you might try clearing the Multiply Strength by Rest Length for each curvature bone if you haven't to see if your undesired deformation goes away.

    mTp
    Yes, it works much better, also I was using a wrong subdivision order.
    I still have some problems with the high poly mesh which cause strange deformations but for my needs is fine now.
    Thanks everybody!

  11. #11
    Axes grinder- Dongle #99
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    Your final approach would be appreciated here.
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

  12. #12
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    Quote Originally Posted by jeric_synergy View Post
    Your final approach would be appreciated here.
    The bend deformation tool is what works better for me in this case, because I need a clean and rounded deformation which conforms better to the object to animate, and it'll be my final approach for this scene.

    The last bones solution proposed also by mTp is working very well, without the Multiply strength by rest length. Important is to set subdivision order to Last, so it works good with subd geometry. The deformation though is slightly different from the bend tool.
    Here's an example, same mTp scene but with a subdivision applied in modeler, than a subpatch and order set to last and subdivision level to 12:

    Click image for larger version. 

Name:	bones.gif 
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