I use onion skinning for 3D and will try to give feedback based on my experience.
I’ve tried multiple add-ons that draw ghost frames in Blender and most of them are unusable for me, and the reason is that they do something that is also in your video. Ghost frames look exactly like the original mesh. Unless you have object selected it becomes impossible to see original frame. There’s also no difference between previous and after frames. It becomes visual clutter. I use addon called Animation Extras which is free and has onion skinning that draws like this
It is extremely helpful. Ghost frames are invisible, so you can see through them if you have something behind. They’re clearly different from original, difference in previous and after frames too.
I think there needs to be general Previous and After ghost frame color in theme that will work on every type of object including Grease Pencil, and if you have multiple and want to differentiate you can override on object level and set custom colors. Similar to how viewport material colors work I guess.
Also UI is very important. This is the UI from add-on that I cleaned up
- Ability to choose Before and After ghost numbers separately, so you can have 1 previous and 3 after for example
- Ability to display either around frame, or entire range, like Motion Paths.
- Frame Step is also something I work with all the time, when spacing is too close it helps a lot
- Color and opacity controls are also nice. Start and End values below colors create gradient, so that frames closer to current frame are more visible than ones at the end.
- In Front/In Back also helps a lot if you have multiple objects and they’re intersecting with ghost frames.
Looking at the video perfromance seems amazing and real-time updates are top notch. I also like ability to disable them from overlays