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As the title says, I have a peculiar problem with my project. I want to have my armature follow the spiral path but in some places (as I deducted It occurs under a specific angle of rotation) every bone, except the root one, does the 360 flip. enter image description hereenter image description here

I'm not a master of animation and it's my first time using the bone constraints so it is possible that I've made something wrong. I've been following the steps from this tutorial:

https://www.youtube.com/watch?v=2aXjzxI6kXY&list=PLrslMsysRiQxDgLq0bpGpQfOsmRSb_YX_&index=3&t=111s&ab_channel=MaxZhangLearn3D

The key is There's a plane following a curve using a curve modifier with an armature assigned to a few vertex groups along the plane. Each of the mentioned bones has a constraint copying the rotation and locations from their own vertex group of the plane. They have a 'Strech to' constraint as well assigned to the vertex group ahead.

The spiral is from the blender's add-on 'Extra objects' and is made of nurbs. I've cleared the tilts even If I had not applied any so It's not a matter of the curve. I've checked and each point has a tilt of 0 degrees. I've tried to track the self-made path and the problem has repeated. The problem occurs in a few places all over the logarithmic spiral and all of them are in the same vertical axis. It shows the pattern of the conditions where the problems occur. It has to be something with bones and their constraints. I followed this tutorial because I want to have some sort of control over the rotation of the points on the path so I could be rotating specific segments of my model on its way through the path. The plane followed by the armature has the same rotation all the time and even at this particular point The strange rotation did not affect seemingly the plane itself but only the assigned bones.

I've followed this tutorial once before using a simple chain of bones and it worked perfectly but actually, I'm not able to achieve the same result. I would be glad for you to help because this element is a very important part of my bachelor project. :') It is one of the segments of the much longer sea snake but I wanted to test animations on the smaller part.

Here's my blender file to view.

RiRu
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  • i can't use blender right now. Is your root bone's rotation mode set to quaternion or euler (and which axis)? – L0Lock May 29 '23 at 21:18
  • It's quaternion. Other bones are quaternion as well Edit: Pardon, I checked wrongly. They were Euler XYZ but even switching to Quaternion doesn't changed anything – RiRu May 29 '23 at 21:25
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    Quaternion can't do rotations over 360° so it definitely wouldn't have helped, and Euler with the wrong axis for your animation can cause a gimbal lock that can look like this. But it looks like @Chris got the answer – L0Lock May 30 '23 at 14:12
  • Okay, thanks for the explanation! I will consider this when another problems occur, hah! – RiRu May 30 '23 at 20:22

1 Answers1

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on the stretch to constraint, rotation, check the zx

enter image description here

result:

enter image description here

Chris
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  • Woaah, huge thanks! I'm gonna check if it's gonna work with the entire model. I hope everything will go fine. – RiRu May 30 '23 at 20:21