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Okay, so I have a mesh that has a tail so I googled how to rig the tail and it said to use a Spline IK restraint. I built the spline on the bones of the tail and now when I move the whole armature, the bones connected to the Spline IK do not follow. The picture shows that when I move the armature, the tail bones do not follow. This situation is a problem.

I am rigging this dragon for school. I am down to a couple days to finish this but I am having issues. When I move the master bone of the armature, the spline IK I made does not follow. Why does this happen?

Broken brokenRig rig This image shows what happens when I check the chain offset box This image shows what happens when I check the chain offset box

LightOfTheNight
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  • Please improve the clarity of your question. Please do not rely on the 1st degree clarity coming from a file. When the reader looks at the images, the reader can be told by explicitly if something is good or bad or other classification. Spline IK allows an armature bone sequence to follow a curve. All constraints can be composed for further effect. You write .. [When I move the master bone of the armature, the spline IK I made does not follow.]. It is a common mistaken situation for people to believe that a constraint will just work in their situation automatically. – atomicbezierslinger Jan 22 '19 at 17:36
  • So how do I make the Spline IK restraint to move with the armature? I know what it does, and used it on the tail. I just do not understand how to make it move with the armature. @atomicbezierslinger – LightOfTheNight Jan 22 '19 at 17:40
  • From what you wrote if appears you have a mistaken basic concept of what the Spline IK constraint offers to do. https://docs.blender.org/manual/en/latest/rigging/constraints/tracking/spline_ik.html . Of course their are video tutorials on video websites. What do you want the Spline IK constraint to do? Do you think you have used the Spline IK in a way that matches its description in the link above? Again constraints and Python drivers can be layered. One suggestion is to show additional pictures for people who may not feel it necessary to open your .blend file. – atomicbezierslinger Jan 22 '19 at 17:42
  • I read your statement in the comment. Please differentiate clearly between the tail which is a part of or a total armature and the [armature], The language is not clear to me. – atomicbezierslinger Jan 22 '19 at 17:44
  • Okay, so I have a mesh that has a tail so I googled how to rig the tail and it said to use a Spline IK restraint. I built the spline on the bones of the tail and now when I move the whole armature, the bones connected to the Spline IK do not follow. The picture shows that when I move the armature, the tail bones do not follow. @atomicbezierslinger – LightOfTheNight Jan 22 '19 at 17:48
  • The title of your question may make some people think you do not have a basic understanding of Spline IK constraint. Typically Spline IK constraint causes a bone chain to follow a curve and not vice versa. Perhaps you may want to change your title of the question of content of the question to .... ... How do I get the rotations of an Spline IK constraint and not bone origin changes. – atomicbezierslinger Jan 22 '19 at 18:04
  • Your last comment is the most clear statement and should be incorporate into the original question. If you want me to see in particular ... you can write ... see my new edit please. – atomicbezierslinger Jan 22 '19 at 18:07
  • What is the average movement you want from the tail? What is the most coordinated and complex movement you want from the tail? How much time are you willing to dedicate to some in depth understanding of this. Do you just want some movement that works for today? – atomicbezierslinger Jan 22 '19 at 19:11
  • I probably wont see more of this question for 48 hours. Your question would be clearer if you labeled each image. – atomicbezierslinger Jan 22 '19 at 19:21
  • Thank you for your help! I am going to manually move the Spline IK independent of the armature due to not having time to fix this issue. I did try to title the images but do not fully understand posting on this forum I guess @atomicbezierslinger – LightOfTheNight Jan 22 '19 at 23:52
  • To the OP and anyone else stumbling on this post, I found this answer which helps to explain and provide a workaround for the Blender limitation of combining spline IK with other forms of rigging armatures. https://blender.stackexchange.com/a/35442/58258 – Arthur Bullock May 06 '19 at 22:40

2 Answers2

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The spline which determines the bones, and the empties running the hooks controlling that spline, are unparented. Select the spline and all the hook controllers, then shift select the armature and enter pose mode. Select a bone-- I recommend "Lower Back"-- and ctrl p parent->bone relative.

Nathan
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Showing a bone chain controlled by a Spline IK Constraint

Image above Showing a bone chain controlled by a Spline IK Constraint

Consider using the Chain Offset feature as enabled . This is indicated by the yellow arrow.

  • Please know there is a technique in modeling with regular IK constraint where there are 3 models. Model 1 tweens or has a linear interpolation of the other two models. Bones capture rotation, so rotation can be interpolated. Depending on your level of experience and patience this technique can be appropriate or in appropriate.

  • Bones can have a copy rotation constraint.

atomicbezierslinger
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  • I tried this and it moved the tail off of the curve. I have added a picture for you to see @atomicbezierslinger – LightOfTheNight Jan 22 '19 at 18:20
  • I understand that you may think that situation is a problem. I ask you ... Why is that a problem in your scenario? I wont have time to investigate this fully and I have seen this situation before. If you do try to change this you may not like the battle which may be time consuming. In the battle you may get valid or arguably invalid messages in the Console ... such as ... Cyclic dependency detected. Please see comment above in original question. – atomicbezierslinger Jan 22 '19 at 19:08
  • I make the comment about Cyclic dependencies because some people may validly criticize Blender in regard to this type of situation over which you and other people have little control. Lastly with certain setting in the Spline IKC you can get results that you probably do not want depending of curve length, so there is not always a one to one correspondence. – atomicbezierslinger Jan 22 '19 at 19:25