Retiming animation is changing it

[kariomart]

Animation retime issue.c4d
I want to retime an animation, but when I move the animation's keyframes on the Dope Sheet, it changes the animation's path.

In my file, I have the original animation and then a copy where I simply moved up the starting keyframe. In my second copy, I have what I am actually trying to accomplish, which is the hinge animating, holding for a moment, then reverse animating back to its original position. The issue occurs in both copies.

[kariomart]

Animation retime issue.c4d
I keep trying to post my .c4d file and keep getting the notice "error".

[kariomart]

Here is a Google Drive link for the project file: https://drive.google.com/file/d/1IivesGaeZhcWmH2vFxSBx5HrgwXjxG-D/view?usp=share_link

I realize outside links shouldn't be used, but I keep getting "Error" when I try to upload.

[Dr. Sassi]

Hi miss-bear,

Thanks for the file. I assume it is a file-size issue. Sorry about that.

I have explored several cloud services. I am fine with Google, Adobe, Apple, Wetransfer, and Dropbox. (Zip files are the problem, but I take extra care about those). Each research took me some time, so I do not take other cloud services. This means thank you for using Google.

Here is your file back.
The setup on the Orange layer is set to 300 frames, but adjust the animation to any duration.
https://stcineversityprod02.blob.core.windows.net/$web/Cineversity_Forum_Support/2023_PROJECTS_DRS/20230414_CV4_2023_drs_23_CAan_01.c4d.zip

The idea, in this case, is that the symmetry in your setup can be used to drive this with XPresso. This means the Ease in and Ease out of both previously used curves don't have to match, as the second one isn't there anymore. Whatever the first joint does, the second will counter and keep it symmetrically.

BTW, your Joints are not equally long. In the file above I left it as I found it.

Let me know if that works for you.

Have a great weekend.

[kariomart]

Hi Dr. Sassi,
Thank you for this (and all the info on CAD models). I don't know any Xpresso, so this is an interesting approach, but I need to keep the curves exactly as they were. This is still the door of the model you helped me bevel and if this file weren't so stripped down, you'd see that the end of the joints runs on a track, which I keyframed and adjusted.

Even outside of this example, I feel like I've keyframed things in C4D countless times, then used the Dope Sheet to move around keyframes to retime, without affecting the animation. Is that not the case, or is it something to do with these being joints? Have a great weekend too!

[Dr. Sassi]

Hi miss-bear,

Yes, you can typically use the keyframes. If you like Symmetry in animation, then it must be a precise fit. Please compare the two curves of your original animation; they do not match. If you change it, it falls apart.
I wanted to make it simple for you with XPresso. The Xpresso part takes the animation from the Top Joint and provides the needed data to the second joint; in that way, the curve interpolation is the same, and you can adjust it as needed.

CV4_2023_drs_23_CAan_02.c4d

I can understand; if you feel uncomfortable with this, please look at the file below. In the image, you see some data. Whatever is in that field needs to match your setup.

All the best

[kariomart]

This post is deleted!

[kariomart]

Hi Dr. Sassi,
Thanks as always, however I am unconcerned with symmetry and don't want to involve Xpresso if possible. I want my animation to remain EXACTLY how it is. I simply want it to animate, hold, then reverse the animation back to its original position.

I have a previous version of this project where I did this successfully, simply by copying/pasting keyframes, and I don't know why it works here and not in my current project. Here it is (still getting the "Error" message" even though it's <2MB):
https://drive.google.com/file/d/1k5m9ftPT1L88SX9sLqVmDFe35C7tdxuX/view?usp=share_link

[kariomart]

Another update! I followed your advice and unchecked "Remove Overshooting" and "Automatic Weighting" (in my current project) and the animation now plays as I want it.

Since I'm trying to understand this conceptually, I still don't understand how I can speed up or slow down this animation without it being altered. If I highlight all my keyframes and use the little 3-line icon above them to scale them to 50%, the joints go off track. And more broadly, If you have a scene that is intricately animated with lots of curves and customized keyframing and now you need everything to animate in half the amount of time, how would you do it?

[Dr. Sassi]

Hi miss-bear,

The point I made above is that you need to have the same settings. Taking overshoots out was not meant as a rule.

In the initial example, the Key settings were different for the second Joint than the first. That might work sometimes, but more often, it doesn't.

The first Joint does something that the second joint need to do while countering the movement of the first, as it is a child of the first. Any slight derivation from the settings will lead to different results.

When I select your first example, Keyframe 75 from Joint and Joint.1, the fields show Mixed or [ - ] in many areas. There should only be one Mixed, and that is the Key value. These two values should be like "positive two" and the other "negative one", in ratio to each other.

All the best