Particles Texture Sheet

GlowingPotato

Hi!

How can I create awesome texture sheets for particles like smoke and fire to use in game engines like Unreal or Unity ?

Can I use Maya Dynamics to render this ? Is there any developed workflow you guys use for stuff like this ?

Eric Chadwick

Hmm I wish there was some kind of online resource, like a wiki or something.

RN

There's a great article in here:
https://simonschreibt.de/gat/fallout-4-the-mushroom-case/

They mention baking a smoke loop but don't say how it could be done, so that's still a problem.

They do link to this other article that talks about looping using a combination of static textures:
https://zoltane.com/pages/unreal/drone-alone/smoke-material/

GlowingPotato

@RN
That's is very cool!

Iam trying to figure it out how to render frames of a dynamic fluid with alpha channel enabled. but I don't even know how to light the fluid. would depend on the scene I'll use ? damn this is complicated.

RN

I don't use Maya, I hope someone else can help you with the software-specific.

In any case, I'd try rendering an image sequence using an orthographic camera, using a translucent material for the fluid or smoke. You should find some Youtube videos or the Maya docs to see how to do that.
The output format should be 32-bit PNG or TIFF or any other format that supports alpha-channel transparency. You're using an image sequence instead of video because it'll be easier to merge into a flipbook texture or do some post-processing.

Making it loop seamlessly is pretty difficult.
I'm thinking if you can duplicate the particle-emitter object and make sure that the duplicates have the exact same settings and random-seed value, you should be able to render a loop in this way:

This is like a timeline. The red and green bars are the lifetimes of the duplicate particle-emitters. You render the timelime section that covers the yellow part, which is the original emitter.

In this arrangement the start and end look the same, one emitter ends while the other is beginning. Adjust the overlap and particle settings until it looks seamless (maybe 50% overlap?).

If that doesn't work you'll have to do the looping in post-production. Try rendering more frames than you need, like rendering 158 frames if you need 128, so you have 30 extra frames.

Import all frames into some compositing program and cut those extra frames from the start and put them on a bottom layer that fades in and takes the place of the top layer at the end of the sequence, so the last frame of the sequence leads to the first, making it look seamless:

At the end you have a looping sequence of the desired length, 128 frames.

GlowingPotato

RN said:

I don't use Maya, I hope someone else can help you with the software-specific.

In any case, I'd try rendering an image sequence using an orthographic camera, using a translucent material for the fluid or smoke. You should find some Youtube videos or the Maya docs to see how to do that.
The output format should be 32-bit PNG or TIFF or any other format that supports alpha-channel transparency. You're using an image sequence instead of video because it'll be easier to merge into a flipbook texture or do some post-processing.

Making it loop seamlessly is pretty difficult.
I'm thinking if you can duplicate the particle-emitter object and make sure that the duplicates have the exact same settings and random-seed value, you should be able to render a loop in this way:

This is like a timeline. The red and green bars are the lifetimes of the duplicate particle-emitters. You render the timelime section that covers the yellow part, which is the original emitter.

In this arrangement the start and end look the same, one emitter ends while the other is beginning. Adjust the overlap and particle settings until it looks seamless (maybe 50% overlap?).

If that doesn't work you'll have to do the looping in post-production. Try rendering more frames than you need, like rendering 158 frames if you need 128, so you have 30 extra frames.

Import all frames into some compositing program and cut those extra frames from the start and put them on a bottom layer that fades in and takes the place of the top layer at the end of the sequence, so the last frame of the sequence leads to the first, making it look seamless:

At the end you have a looping sequence of the desired length, 128 frames.

Thanks a lot for all this information! Really helpful!
I'am looking to make the particle fade to death instead of looping...what you think ? bad idea?

RN

I think you're confusing what "looping" means. It just means that whatever is happening at the end leads to the beginning, in a way that you can't tell where the thing starts or ends. 

So you can make it loop with the particles fading out, moving, growing etc. 

That article I linked to has an example of the looping smoke texture they used in Fallout 4. 

It loops with fading:

(Image source: Fallout 4 – The Mushroom Case)