Feedback Each Particle System takes up ~ 112KB after being serialized in prefabs locally in Unity 2018.4.10f1

Hello!

I recently figured out that there are prefabs of tremendous sizes in our project, somewhat above 1.3MB. In my impression, prefabs are usually of 1KB-ish size.
After looking into the serialized files, it looks like Particle System is the culprit.

I first removed two particle systems from a prefab, and the file size decreased by 225KB.
Then I created a new GameObject in the scene, only added a particle system to it, then made it a prefab. It took up 114 KB in total.
So that means one particle system takes up roughly 112KB.

And, by checking the GameObject.prefab in the second test, it looks like the file is mostly made up of particle system related settings. It expanded from line 5 all the way to line 4700.

I wonder if this gets fixed in later versions? And does it affect runtime efficiency too?

Using Unity 2018.4.10f1 currently. Thanks : )

 

This is a very annoying issue for us. We did some benchmarks and found that for our project, particle systems affect load times on runtime and overall build times for asset bundles significantly. It took 8 minutes less to build asset bundles ( down from ~ 18 minutes ). I don't have good data for the load times yet but it noticeably improved for scenes that used to have a lot of particles.
On top of that particles make up 80% of the prefab file size. It contributes 31 megabytes to the overall download size of our android builds.
I manually removed the serialized data for disabled particle system modules in all prefabs and it drastically reduced the file size. Of course the data gets put back once you save the prefab again but it just did it to see what it would do to the file size.

I would suggest to add a feature where you can opt in to not serialize disabled modules. I think in the normal case modules don't get enabled by code on runtime. That would already give most of the benefits.
To me that seems like an easy change that doesn't break backwards compatibility.

Looking forward to a response. Thank you.

 

Even if you had a fix available, chances that it lands in 2018.4/2019.4 LTS are pretty much zero I assume?

I thought Shuriken is considered legacy already and doesn't receive much attention anymore. I thought all resources go into VFXGraph. That's not the case?

 

I just looked at the .prefab file what's actually stored. Excuse me if I'm going to point out the obvious.

It seems mostly curves cause the bloat. Every module contains at least two curves (minCurve, maxCurve). I imagine many curves might be left at their default values.

Getting rid of the default curves might significantly reduce the bloat. If module stripping is too difficult, perhaps curve serialization is the easier route to go?

I've of course no idea how serialization in Unity work, so my assumptions are likely to simple. But from an outsiders perspective, when serializing the file, one could check if it's a "default min or max curve". If it's a default curve, "set it to null" for serialization, so it does not end up in the file. If the deserializer detects "a null curve", create the corresponding default min/max curve for it.

 

Is there update on reducing the ParticleSystem serialized data, please ?

 

Just stumbled upon this in my project, and yes +1 to fixing the bloat, serialized particle systems seem to be massively full redundant data.

 

requesting a update on this, i think it would help download size of a lot of android and ios app's....

@karl_jones

 

@jannysice how did you strip the module data out? I'm editing the text file of the prefab to delete modules, but the build size is unchanged,

@karl_jones does the build process add the missing data again?

 

Hi, is there any update on this issue? The problem exists on 2021.3 also