I am using 3D and timeline. I add keyframes to my timeline in the mesh section. Everything works fine. But if I save, close and reopen my file, all of the keyframes have disappeared. I have been struggling with this problem for months, with all kinds of different files. I try to render, to export, to do what I can in order to recover my keyframes once I save, close and reopen. It sometimes works, sometimes it does not and I lose hours of work...
I am using a powerful macbook pro, Catalina and Photoshop 2020.
But I already had the same problem with Photoshop 2019.
I also have the same problem with my macbook air, and the same problem with other files.
So it seems to be a problem independant of the machine, the version of photoshop, the version of MacOs and finally the file I am using.
Sorry that there are some missing frames in your 3D file when you save it and reopen in Photoshop 2020.
How many layers and frames are there in your document? If it's a GIF file, this discussion might help: https://community.adobe.com/t5/photoshop/gif-missing-frames-when-opened-in-ps-20/td-p/10146723
I am also having this problem. Even with just 1 layer, when I add keyframes to a 3d object, the keyframes do not save. And this is using Photoshop 12.1.2 to make the file. Unfortunately that thread regarding GIF frames didn't address the issue since this is a keyframe issue for timeline animation.
After testing it a few times, it looks like the keyframes DO save, but only appear when the stopwatch icon is clicked in the relevant later category (ie. 3D Meshes>"Name"). Then all the keyframes appear.
This is unlike the other, non-3d layers with keyframes, which display the keyframes simply when the layer view is expanded in the timeline, and do not require the keyframe/stopwatch icon to be clicked. But at least they are saved!
I assume you mean keyframes. I find 3D keyframes buggy in Photoshop but do the following to try and work around it.
1. Add keyframes
2. Immediately save the file.
3. Close and reopen the file
4. Check keyframes and if required repeat 1 to 4
5. Render video.
It sometimes takes a couple of repeats before all keyframes stick.
I am having that same issue
I have same issue also. Some times it saves keyframes other times it does not. Even with only two layers one mesh one material. Photoshop 2020 and 2021. The 3D animation timeline is now almost unworkable. It has become very buggy indeed.