How come the "do not dispose" option in photoshop doesn't have any effect on my stopmotion animations when I import them in After Effects?

Question

Hi,
i'm trying to create an animation in photoshop. It's a sort of spiral shape that appears bit by bit.
I'm drawing different frames, but each frame is build onto the previous frame. So i don't have to redraw to part that came before the new part:
So first i drew all the different frames (yes they have transparent backgrounds). Then I selected all layers and went to window > animation.Here I made frames from all the layers and converted it to a frame animation. here I selected all frames and selected " do not dispose" because I want all the previous frames to stay visible when a new frame appears.
Then  I did export >render video
file options:
image sequence: photoshop
range: all frames
render opt: straight
frame rate: 20fps
Now I get all the different layers as PSD files. After this I imported the files in after effects:
file>import >multiple files 
import as: footage, photoshop sequence, merged layers
this gives me a single animated file with all the frames behind each other. But the "do not dispose" option has no effect here. I just shows all the different frames, but it disposes all previous frames. Instead of this as a final frame:
I get this:
Can someone help me with this? I'm kinda new to animation.

Answer 1

An image sequence is an image sequence is an image sequence. AE does not care for specifics of PS' internal animation system and that is that. I'm also not clear why you choose to import as multiple files. A simple image sequence surely would do the trick?!
Mylenium