Articulated Skeletons in Rhino

Discussion in 'Gallery & Designs' started by Willja67, Nov 11, 2006.

  1. Willja67

    Willja67 Member

    Hey everybody and most particularly Rhino gurus I'm starting my Eagle project and I have been tinking how I want to go about it and have decided that I'm going to build a skeleton of the bird in Rhino that can be articulated so I can get different poses then I'll build the feathers over that once I've settled on the shape I want.

    Thing is I don't have a very good idea about how to go about doing that. I'm not going to make the bones with their exact shape my idea is to use simple cylinders and the like and was wondering if anyone has any experience doing similar things. If not you will all get to see my feeble attempts as I see if this idea has any merit but I know some of you can help so please do.

    Establishing easy to use pivot points will be the most crucial part of this project I think. So any tips will be appreciated.

    I'm done rambling for now.
  2. wunwinglow

    wunwinglow Active Member

    Rhino doesn't have any mechanical 'linkage' systems internally, but the plug -in called Bongo (it is a big african deer!) is exactly what you need. I'm not sure of the price, but there is a demo, . Be prepared for another learning curve however!!

    (Will, knowing you, within a couple of weeks you will be posting movies of your F2G starting up, taxying to the threshold and flying off into the sunset, gear and flaps all tucking away........)

    Tim P (wunwinglow)
  3. marian

    marian New Member

    To arrive at a general idea I think standard Rhino may suffice.

    I just played around with a very quick example: I started out in one
    plane and just placed cylinders of varying diameter.

    As there is no hierarchical grouping in Rhino you have to be careful selecting.
    To pose one "bone" you have to select it and all the lesser ones attached to

    Then you can rotate around the base point, easily snapped to by the good
    settings of OSnap.

    Rotating in different planes can be achieved by the Rotate3D command, add
    short straight lines to the "joints" to mark the axis they rotate about. You
    could group these with the "major" bone in the joint, that way the rotational
    axes would get transformed with the bone and the spatial relationships kept.

    Of course these bones would not really be attached to each other in any way
    and not buildable like this. But I think after posing them all you could create
    "node structures" that could be used to mount them in the desired angles. Or
    maybe replace the cylinders with flat surfaces that can more easily be cut
    out from strong card and slotted into each other and/or the nodes.

    Attached Files:

  4. lizzienewell

    lizzienewell Member


    I've been doing articulated wings for my science-fiction ekranoplan. I based the design on birdwings.

    My wing spars are polystyrene strips. I tried making it out of paper but had difficulty with ridgidity of the hinges. The hinge pins are wire and the rib/formers are paper. The skin is stretchy nylon fabric. You won't need to do the fabric part becasue I expect your model will have feathers instead of an aircraft type skin.

    The ends of the wings are fans. A thread going between each "feather" to keep them from expanding too far. I had to use fabric reinforment in the "feathers" because the thread kept pulling out of the paper.

    The wing has "tendons" which go across the parallelagrams of the wing structure. One tendon is of beading elastic and the other of thread, so that the wing position can be adjusted by pulling the thread. The other tendon acts as a spring.

    I think that a bird wing will be slightly simpler since it will have a single leading spar and not the trailig spar. The feather parts are going to be more complicated then mine since the fan construction would be over the entire wing.

    I think that you've seen my wings already. Thank you for helped me with figuring out the wrist articulation that allows my wing tips to go dihedral.

    The hinges for an articulated wing need to be more durable than hinges for a wing that folds for storage. This is why I went with plastic for these parts. Paper hinges may work though if the model is bigger than mine. Mine is about the size of a chickadee.

    I was thinking about all of this while driving this morning and saw an eagle--a good sign.

    Attached Files:

  5. lizzienewell

    lizzienewell Member

    Woops I re-read your post and realized that it was about animating articulated wings using Rhino, not about articulating actual wings. Sorry.

  6. Willja67

    Willja67 Member

    Tim and Marian thanks for the help. I was wondering does rhino do solids like autocad? If so maybe the best thing to do would be to create a sphere on the end of each cylinder and that would make selecting the pivot point easy just osnap to the center of the sphere.

    Lizzie, It's hard to beleive that I totally forgot about all your work when thinking about this project. You may have just opened a pandoras box and I may have to be admitted to the funny farm before the end. I am totally confident in my ability to create a fixed pose of the bird the only question is how long it will take me. I like many people am always looking for higher mountains to climb and I may have to blame you for pointing out the one that I fell off of. I think the first order of business will be to create a fixed pose then see if I can get it to move. Lizzie I may have to shoot myself cause of you.:twisted:
  7. marian

    marian New Member

    Just draw a straight line across the diameter of the cylinder at the base. you can OSnap to the halfpoint of that line. If you make the line longer than the diameter but still centered it can double as axis for Rotate3D.
  8. Gil

    Gil Active Member

    It's easier to do than you might think. Only problem is you start into an animation sequence and the next time you check the clock you realize that the Sun is about to rise...,


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