Unreal Engine 4 sub sim project: Sub^3

[nopoe]

Technical details on what I managed to accomplish:

While poking around in the USML codebase I figured out there are faster but more approximate ways to do some of the things that I was doing, so using those I managed to get the average time between updates down to 0.7 seconds per contact at 20nm spread across all cores. Instead of replacing the linear algebra library, I decided to eliminate one very expensive matrix operation and replace it with a bunch of individual scalar operations. That brought computation time per contact down to 0.5 seconds. I'm thinking that's adequate.

These computation times are calculated based on the average time for 4 separate benchmarks to run to completion divided by 4. There's a little more to it than that, but it's important to note a single computation actually takes around 2 seconds, but there are 4 happening at once so you'll get one update every 0.5 seconds on average.

So now all that remains is creating the actual game.

[magicstix]

Originally Posted by nopoe

So now all that remains is creating the actual game.

That's a very important point. Usually what I see sinking hobbyist projects like these is focusing on the wrong things too early. Yes, it's good and cool to have a super accurate acoustics model that makes former sub sailors think they're at sea, but if you spend all your time on that early and burn out, where's the rest of the game?

The best thing to do is focus on the fundamentals early on. Get your entity system done, get your network communications done, get a game going before adding the flash and bling. Don't worry about the ocean modeling until you have a sonar display, use 20 log R propagation and get dots stacking on your simulated broadband waterfall first. Playability beats pretty any day.

[nopoe]

Originally Posted by magicstix

That's a very important point. Usually what I see sinking hobbyist projects like these is focusing on the wrong things too early. Yes, it's good and cool to have a super accurate acoustics model that makes former sub sailors think they're at sea, but if you spend all your time on that early and burn out, where's the rest of the game?

The best thing to do is focus on the fundamentals early on. Get your entity system done, get your network communications done, get a game going before adding the flash and bling. Don't worry about the ocean modeling until you have a sonar display, use 20 log R propagation and get dots stacking on your simulated broadband waterfall first. Playability beats pretty any day.

All I was doing is making sure my goal was possible. I'd hate to get something playable without an acoustics model and then realize I was going to need to model all the acoustics myself because the libraries out there weren't fast enough. I simply do not know enough math or physics for that, and it would permanently stall release unless somebody else stepped in and did it for me (unlikely, but it's open source so it could happen). I'd hate to get to that point after a few months of work or more. It's much better to assess all risks up front, especially the ones that have the potential to prevent the project from becoming what I want it to.

Like I said in the original post, we're using Unreal Engine so it already has an entity-component system and the networking code is written for me. I just need to use some preprocessor macros before variables and the engine takes care of the rest.

I've properly finished a few hobby projects before, so I totally understand what you're trying to convey, but benchmarking USML made sense for me. I don't want to make something that isn't as good as what's already available, because then nobody would have any reason to play it.

Unfortunately my graphics card died on me today so I'll need to take a break from the project for however long it takes to get it RMA'd. Maybe a week or two. The unreal engine editor doesn't run on integrated graphics.

[TheGeoff]

Very interesting!

When I started implementing sonar / acoustics modelling in my sim, I spoke to a couple of ex-submariners, did some research and basically found that truly accurate simulation of underwater acoustics would be almost impossible - there are just too many factors to consider. The temperature of the water, turbulence, currents, the material of the seabed (rock, sand, silt), the frequencies of the sounds involved, and so on... I coded my own fairly simple, abstracted model in the end.

I'm extremely interested to see what you come up with - you're clearly taking a far more mathematical approach, and making use of some pretty powerful libraries. Best of luck, this is definitely a project to watch!

[magicstix]

Originally Posted by TheGeoff

Very interesting!

When I started implementing sonar / acoustics modelling in my sim, I spoke to a couple of ex-submariners, did some research and basically found that truly accurate simulation of underwater acoustics would be almost impossible - there are just too many factors to consider. The temperature of the water, turbulence, currents, the material of the seabed (rock, sand, silt), the frequencies of the sounds involved, and so on... I coded my own fairly simple, abstracted model in the end.

I'm extremely interested to see what you come up with - you're clearly taking a far more mathematical approach, and making use of some pretty powerful libraries. Best of luck, this is definitely a project to watch!

It's not impossible; it just takes a lot of computing horsepower. The only model accurate at all frequencies is essentially a finite difference model that marches out in range. A lot of simplifications of acoustic propagation have been made to speed things up, but they only work in certain environments. The biggest problem is low frequencies and high frequencies behave very differently.

[zachanscom]

ocean physics and visuals is far more important. i think the good old feeling of sh3 crashing an rocking in rough seas is a must even in a modern sub sim

[magicstix]

Originally Posted by zachanscom

ocean physics and visuals is far more important. i think the good old feeling of sh3 crashing an rocking in rough seas is a must even in a modern sub sim

I disagree. Considering modern subs rarely use visual sensors like the periscope, realistic acoustics and sonar are the most important parts in a modern subsim, IMO.

[Julhelm]

Originally Posted by magicstix

I disagree. Considering modern subs rarely use visual sensors like the periscope, realistic acoustics and sonar are the most important parts in a modern subsim, IMO.

There's a reason the Sonalysts games didn't do very well and that's because they just look boring to anyone who isn't a hardcore nuke enthusiast. If you want to base your game around a waterfall sonar display don't expect it to shift a lot of copies.

[magicstix]

Originally Posted by Julhelm

There's a reason the Sonalysts games didn't do very well and that's because they just look boring to anyone who isn't a hardcore nuke enthusiast. If you want to base your game around a waterfall sonar display don't expect it to shift a lot of copies.

Financially, DW was a success, however, I'd say the reason Sonalyst sims did poorly is because:

A.) They didn't do much to advance the state of the art since Jane's 688i and had poor realism.
B.) They all had a terrible mission editor.
C.) They all had lackluster campaigns that did not change at all based on the player's inputs.
D.) They all had terrible multiplayer, even DW, which came out in 2004.
E.) Because of D, it was easy for the player to quickly become overwhelmed with all the stations that had to be managed, even with autocrew.