display a 3D animated trajectory

Samuele

Hello everybody, I'm making a pool game and I'm trying to display an animated curved trajectory, a dashed line or a stripe, over the table from the white ball forward (it could be curved depending on the spin).

how can I draw such animated dashed line or stripe over the table?

I don't know where to start, Sprite3d ? drawing on table surface but how?

In my understanding this is not a navigation thing neither is drawing on camera view port because other balls/objects might partially occlude the trajectory, so I'm pretty lost.

thank you in advance

jjmontes

My two cents. I'd consider:

a particle system
a bunch of spheres / objects animated programatically
a custom line in 3D

I think I'd go for the second option, since there are not that many points in such a trajectory and you'd have easy control over appearance and animation.

If however, you strictly want a dashed line or continuous stripe, you can construct the geometry yourself using the geometry builder helpers (https://docs.godotengine.org/en/3.2/tutorials/content/procedural_geometry/index.html). In these cases, the difference between dashed and continuous is usually managed in the texture or shader.

I do not recommend using Sprites for this. It's costly (updating them in video memory) and has more drawbacks I guess.