How to animate a Katana/Sword going out the Sheath?

Hello everyone again. So, today I am following a tutorial to make an action in animation. (I wanted to remove a Katana from its sheath, without the katana crossing the sheath during the animation)
However, a problem occurred during the process, which was assisted by a colleague. And, now I see that the tutorial, despite being very effective, and great, is not quite what I was looking for, but it taught me a little about rigging …
So to finish the process, which started with the tutorial, I would like one last little help today X’D
The question is: How do I move the weapon, from the new controller / bone? What are the options?

Remembering: I just did all this process to make the weapon come out of its sheath in a line / axis without having to cross the sheath during the animation.

The tutorial: https://www.youtube.com/watch?v=W2WsgkI3Iqc

The File:

I didn’t look at the tutorial, just at the file. Did you intend to have an animation demonstrating the katana leaving its sheath and the following problems? I see four actions, but only one of them seems to do anything, and that’s a walk cycle.

Looking at the rig, I can’t really see exactly what you’re trying to do-- I see a long chain of bones with either copy transforms constraints or parenting, eventually reaching michin_espada_hand_R, which has no connection to anything. And that’s mirrored for the sheath.

(And personally, I’m just not interested in watching 16 mins of some random youtube tutorial.)

So, I’m not sure exactly what your goal is, or where you were getting stuck. The constraints you currently have on the rig aren’t enough to get the sword in the scabbard.

But, I’m pretty sure whatever you’re doing, the answer lies in the use of the “apply visual transforms” operation combined with animating the influence of constraints. (An alternative to “apply visual transforms” is keyframing visuals, but I’ve had bad luck with that, possibly just in earlier versions, and I just use apply visual transforms and key manually.)

For example, if I want the sword to move with the scabbard, I might create a “copy transforms” constraint targeting a scabbard bone. Then I would go to the last frame when it moved with the scabbard, keyframe constraint influence and loc/rot/scale; then, advance one frame, apply visual transform, set constraint influence to zero, and keyframe constraint influence and loc/rot/scale.

It’s well worth figuring out what “apply visual transforms” does, but the best way to figure that out is to just play with it. It’s a very useful tool that solves all sorts of animation problems.

You could check out https://blender.stackexchange.com/questions/210021/how-to-unattach-an-object-and-reattach-it-somewhere-else-in-an-animation/210024#210024 where I answered a similar question. That’s using a child-of constraint, but if you squint, you should be able to see that it’s the same problem that you have.

(Just grateful that it’s not actually a katana, but a straight sword. Curve of the katana complicates the draw…)

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Before, the sword and sheath were each one joined in a different bone.
To move the “weapons”*, I needed to move my hands to their respective locations. In this case, the weapon was related to the bone of the hand. And that made it very difficult.
So this tutorial kind of helped me create bones for weapons.
The problem now is:
1º How do I make the “weapon” that has a bone, move with:
1.1- Hand movement;
1.2- “Weapon” movement.

2ºAfter making both movements with both bones, how to:
2.1- Animate the hand / weapon to the point where the blade is no longer in the sheath;
2.1.1- Without the blade crossing the sheath;
2.1.2- Without the hand / arm stretching with IK stretch

Note: It is a riggy made with riggify.
Note 2: Remembering that it’s not just moving the weapon, but moving it without disturbing the animation path.

    • Weapons means both: sword and sheath.

To make it move as if parented to some bone, use a child-of constraint targeting that bone, or a copy transforms constraint targeting something that is parented to that bone. To switch it off, use apply visual transform and animate constraint influence as described above.

Have the hand follow the weapon (like with a child-of). Have the weapon follow the sheath (like with a child-of.) Animate the weapon by translating in a single local axis.

By not animating it crossing the sheath, which is pretty simple in this case because the sword is straight-- if you start in the sheath, and you animate the sword by translation in a single local axis, and you have a reasonably chosen local axis for the sword+sheath like the directions they actually point, nothing will cross.

By not moving the blade so far away that the hand stretches. (You could disable IK stretch on the rigify rig, but that’s not going to help any here-- if the handle is further than the hand can reach, that’s no good either.) If, while the sword is child-of’d to the sheath and the hand is child-of’d to the sword, the arm stretches, then you’ve made an impossible sword or an impossible sheath position. Move the sheath to someplace where the draw can continue without stretching the arm. Because of the constraints, the sword and the hand will follow the sheath.

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So the better choice is remake the “weapons”?

If your weapons are impossible. They look just at the verge of possibility to me, with the sword equal to the wingspan of the model-- yes, on looking more carefully, that character cannot draw the sword, while holding the sheath, without stretching something.