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  • Aiming system with IK

    англійська

Hi everyone !

I'm currently working on a project and i need to do an "aiming system" for my character.
I've read documentations about the system used for the Spineboy and, as it is exactly what i needed, i've decided to reproduce the same model.
So i've done the IK for the arm and the aim constraint target on the torso to the target, and the transform constraints to have a nice movement for the front arm, the head and the torso
But here is my problem, the head and the arm are not following the movement of the target
On the SpineBoy, when you move the target, by the transform constraints, the head and the arm have a nice reduced movement who's follow the cursor, but impossible for me to reproduce it, even with the same constraint values.
So here is my question, am i missing something? have i done something wrong? Can you guys help me

Thanks for your futur answers 🙂

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  • Minotorcq

    • Допис #2
    • Змінено
    • Цей допис на англійська

    • Søren

    • Допис #3
    • Цей допис на англійська

    It's difficult for me to say why you're not able to reproduce the behaviour of Spineboy without seeing how you set up your constraints.
    Make sure that the order of the constraints is correct. For Spineboy the order is:
    First the small bone at the pelvis aim-constraint-target is IK constrained to look at the crosshair bone. This is the aim-torso-ik constraint.
    Then four transform constraints, each constrained to aim-constraint-target with different Mix values. The Mix values define how much they should rotate relative to the aim-constraint-target bone. These are the aim-*-transform constraints.
    And last, another IK constraint called aim-ik which will aim the rear-upper-arm bone at the crosshair bone.

    I hope this helps, else I'd be happy to take a look at the project.

    6 днів пізніше

    Hi Shiu, thank you for your answer!
    The pelvic bone is well constrained at the crosshair, I have no problem with it, it is more with the transformation constraints that I think.
    I tried to recreate the bones and constraints, but it still doesn't work. Only the torso and arm follow the aim
    The 4 constraints are created in a specific order or is it not necessary?
    Thank you for your time!

    • NNick

      • Допис #5
      • Цей допис на англійська

      Have you check the constraints resolve order?
      Say, if your Head IK is resolved/placed before body IK, the result will be overwritten.

      • Erika

      • Допис #6
      • Цей допис на англійська

      Hello! You can quickly make sure that the order of the constraints is correct by letting Spine calculate it for you. You can do so in setup mode, by clicking on the constraints node, and on the Reset button Constraints: Order

      • Søren

      • Допис #7
      • Цей допис на англійська

      The order of which the constraints are created does not matter, but the order of which they are calculated does. You can drag the constraint order in Setup mode. Constraint order is done from top to bottom.

      I've created a simplified setup for you.
      aim-simplified.spine

      Under Constraints there are three constraints.
      first the aim constraint which is a single bone IK constraint that yields the aiming direction.
      then the torso constraint which is a transform constraint that constrains the rotation of the torso bone to the aim bone at 50%.
      and last the head constraint which is also a transform constraint that constrains the rotation of the head bone to the aim bone at 50%.

      If I were to change the order of those constraints to:
      1 torso.
      2 head.
      3 aim.

      the torso and head constraints would be calculated BEFORE the aim constraint, and would result in the bones not rotating at all when moving the IK constraint target aim-target.

      I hope this clarifies. But like I said, it would be much easier to help you if I had any idea of how your constraints were set up. A screenshot of your Constraints nodes would probably suffice.

      You guys are great, thank you so much for your time!
      It was the calculation order all along, now it moves perfectly thanks to you.
      I will share my work as soon as possible with the #MadeWithSpine on Twitter
      Thank you again!

      • Søren

      • Допис #9
      • Цей допис на англійська

      Glad to hear you managed to fix the problem you were having.

      Happy animating! 😃