Allow the use of animated particles without billboarding

[Kuma-Boo]

Describe the project you are working on

A stage hazard using an animated sprite-sheet.

Describe the problem or limitation you are having in your project

I need to be able to rotate the stage hazard to suit the level design, but this is impossible when using a sprite-sheet and the particle animation system since animated particles are billboard objects that don't rotate with the particle emitter.

Splitting up the sprite-sheet and using an animated texture instead solves the rotation, but then all the particles render the same frame due to using the same animated texture resource.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Add a way to use a Material's "Particles Anim" property without forcing billboards.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Remove the "Particle Billboard" option and replace it with an "Enable Particle Animations" toggle. The user could then enable the checkbox and use particle animations with any of the other 3 billboard options, allowing for better flexibility.

If this enhancement will not be used often, can it be worked around with a few lines of script?

I've thought about using multiple Sprite3Ds to try and fake the effect, but that seems like a nightmare to manage.

I'm sure there's a way to achieve this with custom shaders or something, but many beginners (myself included) wouldn't be able to figure it out.

Is there a reason why this should be core and not an add-on in the asset library?

This functionality would improve the usability of the base Particle System.

[RPGgrenade]

I haven't seen this talked about more. But it seems odd that a basic feature such as this, the ability to animate a particle, is locked behind forcible billboarding, and requiring those who just want that and not the billboarding to figure out shaders just for the option to be available. It makes sense in perhaps a 2D context because it rarely makes a notable difference, but if youwanted a flat particle on a surface to animate, you kinda just don't have that option without needing to mess deeper with code, which is very unhelpful for artists on a team.

It's very user unfriendly and it would be appreciated if this were changed at some point.

[Calinou]

• Related to Add a Preserve Orientation billboard property #5591
  and Rework transform align property and promote it to GeometryInstance3D #8367.