How can I do a cartoon-like cannon firing animation that's compatible with Unity (without lattice modifier)?

Question

I am working on the cannon below:

It is going to be used in a Christmas mobile game and is going to shoot presents. I want to make it have an animation where, when I shoot the present, it's a kind of cartoon-like animation where the present goes through it visibly. I asked this question already a few days ago, and actually made the animation, and it turned out just how I imagined. But using the lattice modifier didn't seem to work, because it cannot be used in Unity. Also, Alembic files are not supported by Android, nor iOs. So I need a different method, without the lattice modifier, to do something like this:

What could be the Unity compatible tools to achieve this effect?

Answer 1

Not sure if this is going to work with unity (because i don't use it) But here is a way to get the keyframes.

1: Go to Edit > Preferences > Addons... and turn ON Import-Export New Tek MDD Format.

2: Select the Mesh that is getting the deformation from the Lattice, make a copy Shift + D, delete the Lattice from this copy and put it on a side.

3: Select the Original Mesh again and go to File > Export > Lightwave Point cache (Mdd), put the Start Frame and the End Frame.

4: Select the Copied Mesh and go to File > Import > Lightwave Point Cache (Mdd) and select the Mdd that you exported.

Now, the copy has keyframes

Answer 2

Instead of a lattice, you could rig the cannon with a bunch of bones arranged in a row. How many is up to you... (More bones = smoother animation but heavier asset)

Then animate the scale of each bone up, then down, consecutively to achieve a similar effect to the one you get using a lattice.

There is an addon called Commotion that can automate the consecutive animation offset but that can also be done manually with a reasonable amount of effort.

Here is a bad-looking example but I hope it illustrates the point. (You'll probably want more overlap between the animation of the individual bones)

Alternatively, you may be able to create a similar effect in Unity. It could be an animated displacement shader for example. There may be other techniques. Ask about that in a community focused on Unity3D!