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Automation Tutorial 2: Flying Debris

PostPosted: Wed Apr 04, 2012 9:34 pm
by Daffyflyer

Day 2 of the release countdown - watch our pet german do a playthough of Tutorial 2 :)


Re: Automation Tutorial 2: Flying Debris

PostPosted: Wed Apr 04, 2012 10:22 pm
by AutoHappiness
Curses! I have to put up with waiting to 22th!

Re: Automation Tutorial 2: Flying Debris

PostPosted: Wed Apr 04, 2012 10:41 pm
by svvander
Fantastic! I had the feeling I was in school again! :lol: :ugeek:

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 12:21 am
by Dario
AutoHappiness wrote:Curses! I have to put up with waiting to 22th!


preorder now and can play next sunday :lol:

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 1:08 am
by AutoHappiness
Even though I have to wait, I know the first thing to do when I get it: find the keypress!

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 3:51 am
by Highharti
I think you would set the limiter a bit higher in real life. When it comes to maximum acceleration, the idea is to shift up, when the higher gear offers more power than the current one. You'll never reach that point if the limiter kicks in at maxPowerRpm+100.

There was a similar "issue" in one of the other tutorials. In real life, I'd prefer an engine that has a good power output on all it's rev-range over one, that has a slightly better poweroutput on the top end, but is poor everywhere else.

It's ok for the demo, but in the final game, I think the engines should not only be judged by it's power/economy/lifetime etc, but by its power-delivery-characteristics as well.

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 5:07 am
by Casho
Probably you won't find any real engine that has the same power output at all revs.

The plots are still very near to them of a real engine. The only thing where you can get other plots is with another kind of engine. Maybe with a diesel engine your plot for torque will be different.

Cheers
Casho

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 5:36 am
by Killrob
@Highharti: There are some misconceptions in your post, and I think you mix up the concepts of power (Constant * Torque * RPM) and torque a bit.

A simple model of a theoretically perfect engine would be to have a flat torque curve, just a constant value over the full RPM range. This would give you a perfect linear function for your power "curve", where the maximum power is at the rev limiter - and if the rev limiter would be 2000 RPM higher, maximum power would still be found at the rev limiter. If the engine would allow it, you would always want to run it in lowest possible gear if you aim for maximum power output, because it is completely independent of gear, it is only a function of RPM.

Now for the case of a "real" engine with a power drop-off at high RPM: Yes, you probably don't want to cut off just 100 RPM after maximum... but no more than ~300 either! Short shifting of course won't get you anywhere fast, but long shifting is pretty bad too, the combination of ever dropping power output, linearly rising friction, and quadratically rising air resistance makes you want to avoid going more than a tiny bit beyond the power output maximum... it's a trap!

Cheers
/Killrob

Edit: Also, Automation calculates not only with the maxima, but also with the "peakiness" of the torque curve and its weighted mean... so no worries there. :)

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 6:33 am
by drifting_fifth
Killrob, that was a really really well done post! Which video will we be seeing tomorrow?

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 7:05 am
by Highharti
I don't think I mix up anything to be honest. ;)

This for example is the graph of a 74kW 1.6L engine (VW). Its rev limiter is about 1000 rpm above its max-power-rpm.

Image

This is a 92kW 1.8L Volvo engine, which has its limiter about 500rpm above:
Image

This is a 128kW 1.8L Audi engine... about 1100rpm above:
Image

This is a 270kW Porsche.. about 500 above:
Image

An 88kW Alfa Romeo.. about 800:
Image

A 96kW Fiat.. about 500 again:
Image

A 183kW Jaguar.. about 1500 :shock:
Image


I could go on with this for a while. ;)
You are right that there are engines that have their rev limiter just above their power maximum, or even below it. But I guess they only do that to achieve better lifetimes. From a performance point of view, you'd be faster if you could rev the engine up to the point, where the next gears rpm would give you as much/more power than the current gears rpm.

To give an example looking at the first graph:
If you rev at 6000rpm, and the next gear would rev at 4500 rpm at this speed, it's time to shift up. If you rev at 6000 rpm and the next gear would only rev at 3500 at this speed (that would be steep, but let's just assume), you'd better go all the way up to the limiter. Simply because you have more power at these very high revs than you'd have in the low-reving higher gear.

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 7:37 am
by Killrob
For the specific example you are showing you do have a point yes. On the other hand, that first engine definitely is not a performance engine and not made for driving it as such, I wonder why they put the rev limiter that high up in that case as the engine doesn't look like it likes being up there.

In your example 2, 3, 4, 5, and 7 the maximum power may be achieved at a "much lower" RPM, but it basically is a plateau, for which it makes sense to not rev-limit the engine until it drops off that level. So yes, you do have a point for the specific example you show in figure 1, and in figure 6 you definitely don't want to "drop off the cliff" when shifting.

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 12:27 pm
by manta308
personally i dont care much for limiters, my car develops its max torque and kw at 5100rpm the rev limiter is at 7000 so i change gear at 5100 as there is no point reeving the engine past its power curve other than the nice noise it makes at about 6200 lol

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 10:24 pm
by AutoHappiness
Is it me, or is Killrob's voice the only one that seems to work properly with the Transcribe Speech thingy?

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 10:27 pm
by Equiox
AutoHappiness wrote:Is it me, or is Killrob's voice the only one that seems to work properly with the Transcribe Speech thingy?


He's not human! :shock:

Game is looking superb guys, can't really fault anything!

Re: Automation Tutorial 2: Flying Debris

PostPosted: Thu Apr 05, 2012 10:31 pm
by Killrob
What what what? :D Transscribe speech? From the videos automatically or what do you mean? :) Didn't even know there is such a function.. can you give some more details?