Open up Photoshop, make sure you use a document that's the power of 2
Plan out whatever you want to animate and illustrate it! *note if you make anything in Color, you wont be able to add a particle color and adjust that in cascade later., so I recommend doing it in black and white.
(make sure you have a transparent background for your illustration.)
When your done with your drawing you should be here prepare to animate... well sort of!
For animation, 1 FRAME = 1 LAYER essentially, try and keep it at a minimum, as well as that make sure you work in a moderately high resolution because when you condense everything into a flip book grid later with glue it, depending on how many frames your animation is it will decrease in resolution. don't worry it will make sense later.
I cant really going to far into animation in Photoshop, because it would take way too long to explain, however the gyst of it is using layer opacity to see your prevision layer to draw over like onion shell in adobe animate, an alternate way to make it is using Timeline. There are lots of tutorials on that so if you want to they're out there.
***IMPORTANT*** you should have a squared amount of layers, in other words 2x2=4layers 4x4=16 layers 5x5=25 layers because they are fitting in a grid. note, you dont have to fill each column completely, however keep in mind to try and not go too far past this grid size or else it wont become a square and UE4 will hate you for it.
once your done with making your frames per each animation you should be about here:
Download a program called "Glueit" this is almost literally monkeyjam, the only difference is it compiles all your images into a single png grid next you want to open it up and add all your images. once you have everything, type in your number of columns, just like what i mentioned ealier, if you have 4 images, 2 columns, if you have 16 images, 4 columns ect. adjust your speed(delaymilliseconds) and hit glueit! From there save out your image and your almost done
Take your image from glue it and bring it back into photoshop, add a black background to it so you dont have any more transparency and create your alpha mask, this can be achieved by selecting your layer RGB information and filling it with white, saving that out as a separate .tga
save out all your stuff as .tga files
open UE4 and import everything. From here set up your material
This is how I set mine up however there are different ways you can approach it. I set mine to mask because i wanted my B/W information to read as RGB rather than a mask, I used the mask I made earlier to fix that issue. you could also set your material to additive for a different effect
*NOTE*the multiply with the constant attached to it in the top left adjusts the speed of the animation!
YAY you did it!
all you have to do now is apply the material to a card, or add it to your cascade particle!