Animation with "child of" constraint not working

Hello all,

First post here, and beginner level in blender

I am trying to animate a mechanical construction, which shows how a workpiece is clamped onto a circular plate. I am trying to accomplish the following:

  • a screw rotates 90 degrees and a little metal plate under the head of the screw is moving along with it. This plate has a “child of” constraint to the screw
  • after 90 degrees, the plate touches the L shaped workpiece and thus no longer rotates. This is the part where i disable the child of constraint
  • after this, the bolt is rotated further and the plate is now bended a little bit (using shape key). ( I should note that parts are not drawn yet, which is why currently the bending of the little plate is not physically correct)

The problem is that after the disabling of the child of constraint, the plate allways jumps back to its original location. I tried many different things (adding “locrot” constraints for example) but nothing seems to work.

Can someone help me with this please? Also if you can, please explain why it currently is not working? This is very confusing to me…

See the blend file linked below, thank you.
blend file

Hey, your file contains far tooo much stuff, strip it down to exactly what your issue is and re-post it

Hello,

Apologies! Here is a more simple version:

blend file

Thanks for your time!

I didn’t look at the file.

From fresh, with no keyframes: jump to last frame of child-of influence. Keyframe transform and constraint influence. Advance one frame. Apply visual transform (ctrl a in 3D object mode for me.) It’ll jump-- that’s okay. Set child-of influence to 0. Now it jumps back. Keyframe transform and constraint influence.

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Great, thank you! this works.

I still don’t really understand why it wasnt working before. Is the visual transform command the key to the solution? Can you explain why?

Applying visual transform takes its constrained orientation and turns it into a local space, unconstrained orientation.

I’m glad it worked for the OP, I tried a few times and could not get it to work, must be missing something…

Well, I didn’t look at the file. There can be complicating factors. Although if acisre’s happy…

Usually people don’t follow the order strictly, or they’re not doing it from a fresh timeline. Last time I explained it the person had trouble because they never bothered keyframing the transformation.

If it can be of any help, I added the sovled blend file here:

https://drive.google .com/file/d/1tz-lSOpqB4TLZblKbEJJ2iDi5myIDLAn/view?usp=sharing
(remove the space after google when you copy the link, for some reason I could not share it the way I did before now…)

I will admit that I still find this a little bit tricky and confusing (I think blender should make this easier), and the visual tranform I still don’t exactly understand, but for now, yes I’m happy :slight_smile:

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Thank you - I realized my mistake

I was just using the default Blender scene with the light and cube. I realized I had forgotten to keyframe the lamps location …Embarrassed Emoji
Thanks for the lesson

Thank you, man! I was working hard, trying to make this constraint works. But, don´t you think that the way it works could be easier? I mean, just animating the influence slider? I can´t understand why we must create keyframes for transform, too and use the Apply Visual Transform. I don´t like to compare softwares, but in 3dsmax (I have used it for a long time ago - I prefer Blender, ok? I prefer Blender…), using a constraint like this depend on animating influences only… Does anybody know why this complicate workflow?