How we created fluidmeshes and clouds for Battlefield 1
polycounter lvl 6
Hey!
I wanted to share a video with you. It's a recording of a presentation I held at the SideFX booth during GDC. It covers how we used Houdini to create fluidmeshes and spawnsurfaces for clouds in Battlefield 1.
Hope you find it useful!
I wanted to share a video with you. It's a recording of a presentation I held at the SideFX booth during GDC. It covers how we used Houdini to create fluidmeshes and spawnsurfaces for clouds in Battlefield 1.
Hope you find it useful!
Replies
We tried some volumetric lighting techniques as well, but it caused to many issues and not enough fidelity to warrant it. Simple tricks usually work the best
Can't wait to give it a try, I've been trying to find an excuse to learn some Houdini!
I mean it does look alright but you can get the same or better look through the ray marching method. I just feel like this does not worth the effort. When you can shoot rays and calculate stuff for almost free if you have some certain budget for specific elements of graphics.
You would still probably want to bake it down into 3d flipbooks at the end, but you wouldn't need to go between houdini and your engine. Also it would be pure volume rendering with semi dynamic parameters.
This is just my opinion though.
Anyways, here is a thing to consider. There is the ps4 and pro with some fps and resolution and raymarching still holds up and runs fine...
Also , no sprite and normalmap bullshit...
Still looks fine though...
They're doing that cloud system as the playable level, that's a lot of area to be covering at all times. I dunno man.
Anyways.
There are nice tech papers about ray marching, you should check them out... Its really not that horrible as you would imagine, if you do it in a nice way.
Would you do parallax? Ray marching a volume texture to get different effects is roughly the same amount of stress on your videocard.
As for papers, check this presentation out: http://www.frostbite.com/2015/08/physically-based-unified-volumetric-rendering-in-frostbite/
On Page 42 you can see one of my early tests for the cloudsetup where we still tried to use volumetric shading. There were too many issues when making an entire level out of it so we had to scrap that idea.
Another one we looked at was the Horizon Zero Dawn clouds. While cool, they don't work if you want to fly around in them. They also take up 2ms on the PS4. (Same issues with Simuls Truesky, but with even worse performance) That was the ENTIRE fx budget for BF1. With that, we wouldn't have been able to have a single gameplay effect. With our method, we were able to have dogfights with 20+ planes and two burning airships.
As for raymarched volumetextures, one of the best results I've seen comes from Ryan Brucks at Epic. His tests look cool, but the textureresolution needed for a gameplay area over 1 km across would make a PS4 scream in agony. Not to mention that I was repeatedly told by our rendering engineers that it would too expensive.
http://killzone.dl.playstation.net/killzone/horizonzerodawn/presentations/Siggraph15_Schneider_Real-Time_Volumetric_Cloudscapes_of_Horizon_Zero_Dawn.pdf
As far as I understand, this implementation is even crazier than a normal box volume.
I would show this one for entire level example. Though I don't really have an example for good sorting, in a game. But there is this one by Ryan Brucks. It shows nice lighting, opacity, easy connection with the above noise generation, and some sorting:
http://shaderbits.com/blog/creating-volumetric-ray-marcher
Keep in mind, Ryan didn't start posting about this stuff until a few months after we shipped the game. Seeing as his work is partially based on the Horizon presentation, I doubt he's managed to optimize it further. I mean, look at the end of the Horizon paper, they have already optimized the hell out of it and it still is way to expensive.
Edit: Oh and I do have some insight in the Horizon way of doing it, since Frostbite has done the same: http://publications.lib.chalmers.se/records/fulltext/241770/241770.pdf
http://www.frostbite.com/2015/08/physically-based-unified-volumetric-rendering-in-frostbite/
So I'd still say its becoming "common" to use ray marching here and there, surprisingly often. I would still come up with the same example, its not much more expensive than a parallax with shadows.
Though I would be interested if Houdini could be used to create and bake the volume textures. Normally, using Ryan's method, I would generate and even bake it inside Unreal but thats a pain.
If you are interested in using Houdini to generate the volumes, check out my GDC talk from this year where I show how to do just that. It's in the GDC Vault and is called VFX Bootcamp: Like a Mace to the Face - Leaving the Battlefield to go it alone. It's around the middle in the Houdini tricks section.
If you do find any examples of where raymarching used in a comparable way, please do post them. I'd love to prove that pesky army of rendering engineers wrong.
So there was ray marching used in the latest Battlefield games, to simulate volumetric lighting, and far clouds. And you ended up using sprites for these clouds, because they are very close and could intersect with the meshes?
Did you use lit material for those sprites? Or some sort cubemap lighting?
Thanks for the information though, but for me, this kinda poves that re ray marching method is indeed suitable for games in specific cases. Cool stuff. and yeah I'll probably check out some Houdini 1d to 2d.
Any tipps are appreciated thx
https://media.giphy.com/media/3oKIP5LZTgco7JYyuA/source.gif
If that doesn't help, upload the file and I can check it out in the morning
I am sure it is an absolute beginner problem
Here is a DB link to the file: https://www.dropbox.com/s/sm2mzllkaxfboun/TorusSplash.hipnc?dl=0
i hope the link works...
Let me know how it goes.
I can convert cloud nodes into polygons without problems. Please help.
However, I'm afraid this is as far as you can go with the apprentice edition. Last I checked, you can't export meshes out without buying a license.
The error you got when trying to add things in the skyrig is because it's a locked node (to prevent accidentally breaking it). If you want to add things inside of it (only needed if you know what you are doing) you have to rightclick the skyrig and hit "allow editing of content". Then it'll work like any other subnet.
If you want to learn Houdini get on the "think procedural" discord and the ODForce forum. Most helpful community I've ever encountered.
Check it out!
https://sidefx.com/tutorials/splashmesh-houdini-for-games/