World of AI

Its not really much different polygon-wise than the AIA B747 and I can't recall much complaining about those models killing your framerates.

This is true, but the model that the aia 747 essentially replaced, the FSpainter model, had framerates a LOT worse than the aia model, so that's probably why people weren't complaining.

I did some framerate testing this morning, and here are the results which I'm sure you won't care for:

My testing site is in the Arizona desert, clear skies, about 105 models arranged so that all LODs are in the field of view. The model radius of all tested models has been changed so that they are all identical (for testing purposes). There are no other aircraft being displayed besides the model being tested.

I've seen someone elses more extensive testing results which show an even greater disparity between the AIG and AIA 757's framerates, so I'm not showing "worst case scenario" here.
While poly counts obviously play a part in the framerate performance, it's not the only factor in play. The LOD distances (the distance at which one LOD model shifts to another) also have an effect on fps. The TFS a346 has a quite a bit higher poly count than the AIG757, but still has better fps.

The AIG 757 model is first rate from a visual standpoint, it has all those 3rd generation AI features people want, reversers, XML flaps etc, compressing gear, etc, but it has 1st generation AI framerates.

Of course, you can claim I have an axe to grind, that I'm not a dis-interested observer, so I would encourage everyone to do their own FPS testing and share your results.

David R

How is the LOD distance involved then?

One should shift earlier to LOD2 and LOD3 then?

Looks like the AIA 757's are staying here for awhile...

I believe what we're seeing here is the emergence of 4th Generation AI Models, and while I welcome the improved aesthetics, I think the trend is a slippery slope that is a step back if it’s taken too far.

The so-called 3rd Generation AI Models that make up the vast majority of current AI fleets were very well received when they first arrived and for very good reason. Like their predecessors, they were purpose built AI models, but they represented a sea change because they simultaneously improved both simulator performance AND significantly enhanced aesthetics. It was truly a “have your cake and eat it too” moment.

What we are seeing today is a departure from that philosophy. Developers are beginning to forfeit performance for improved visual appearance. Because of increased computer power I suppose that’s okay if it’s done in moderation. Some of the recent Aardvark models, for example, include aesthetic improvements at the expense of moderately reduced performance (5% - 7%).

I would suggest to you however that the 50% plus performance reduction we see with this new AIG model is in no way moderate. I suppose if it ends there, it won’t be a huge problem. After all, there are only so many B757s flying around, and it isn’t the end of the world if we have a few low FPS models. Most of us already have a handful of odd-ball model types cruising around anyway that aren’t exactly frame-rate friendly.

On the other hand, what if it doesn’t end there? What if AIG and perhaps other developers continue to produce new models with all the right eye-candy but substantially reduced performance? Are we not going to end up right where we started eight years ago with a nice looking slide show?

Obviously the modelers at AIG are very talented and maybe they can go back to the hanger and put this model on a serious diet. Until that happens though, I’ll stick with the Aardvark model. The aesthetic improvements are just not worth the performance degradation. It’s pretty, but I'll pass.

dfreed wrote:What we are seeing today is a departure from that philosophy. Developers are beginning to forfeit performance for improved visual appearance. Because of increased computer power I suppose that’s okay if it’s done in moderation. Some of the recent Aardvark models, for example, include aesthetic improvements at the expense of moderately reduced performance (5% - 7%).

Another downside to this departure is for us FSXers. The extra computer power is needed just to run the primary plane, decent scenery and it's views. AI is still* a hog at med/large airports and we depend even more for frame rate friendly models. I don't think near future versions of FS are going to be any different when it comes to AI, either.

Al

*Just like it was for FS2004 when it came out and most of us didn't have computers to support it.

Well, as someone who is working on a new model, I feel that I should comment. David is right that there has been a continuous improvement in models. For example, the first AIA model, the original 737-300, has only 4 LODs. The v2 model has 9, and despite the addition of new XML coding, and a much higher poly count for the LOD1 (~1000 polys!), gives better frame rates. However, change for change's sake is not always good. I've installed the AIG model, but only becuase it does look much better (sorry AIA!), but the frame rate drop is not too significant, as I mainly fly in Europe, and there aren't that many 757s in Europe. However, if AIG had released an A320 with similar changes, and we still had a model to the same standard as the AIA 757, I might think twice about installing it, as the frame hit would be much bigger. I hope that Jannik has a look at his model. I haven't had a look at the model in ACM, but I'm sure that he can do something. I'll have to be very carefull with this whole LOD business!

I have done a frame rate test as well,
AIA first, then AIG.

Can someone explain to me what is LOD frame rate? I don't see any effect on those picture.

Hello all.

We have taken into account the fact that the AIG model could be a little easier on frame-rates, and have been working on an update to the model which will improve framerates by quite a bit. (almost 50% on my system anyway, but that will vary from user to user.)

The results are promising so far, now we just need to complete our own testing.

Thanks to all who pointed out the small problem.

Andy

Chris Anderson wrote:Can someone explain to me what is LOD frame rate? I don't see any effect on those picture.

There is no such thing as LOD Frame-rate. They are two separate things although the LOD configuration affects FPS.

Frame-rate, or FPS (Frames Per Second) is a measure of simulator performance. The higher the number, the greater the performance. When FPS falls below 25 or so, the simulator starts to become choppy with noticable stutters. At rates below 15 or so the performance is so choppy that you get a "Slide-Show" effect rather than fluid motion.

LOD stands for Level Of Detail. Each AI aircraft model has some number of LODs. For example the AIG 757 has 10 LODs. Each of these LODs is in effect a separate model optimised for viewing at a specific distance. LOD 1 is very detailed (AIG B757 LOD1 = 3708 polygons). This is the LOD that you see when you are close to the aircraft. LOD 10 is very simple (AIG B757 LOD10 = 54 polygons). This is the model that you see when you're far away from the aircraft. The other LODs (2-9) are ones that you see at distances in between LOD 1 and LOD 10.

AndyC wrote:Hello all.

We have taken into account the fact that the AIG model could be a little easier on frame-rates, and have been working on an update to the model which will improve framerates by quite a bit. (almost 50% on my system anyway, but that will vary from user to user.)

The results are promising so far, now we just need to complete our own testing.

Thanks to all who pointed out the small problem.

Andy

Thanks for the update, it seems I might retire the AIA after all.

Chris Anderson wrote:Can someone explain to me what is LOD frame rate? I don't see any effect on those picture.

Look at the left corner where the framerate counter displays the actual FPS.

So the frame rate is important for running FSX smoothly?

No sense in re-explaining stuff that's been well documented before. Go read these webpages:

http://home.sprynet.com/~drawlins/AI_aircraft/AI_aircraft.html

http://www.ai-aardvark.com/modeling/LOD_101/aia_LOD.html

Chris Anderson wrote:So the frame rate is important for running FSX smoothly?

I think you still have no idea what frame rate is...

I'll put it simply...
If your sim is running smoothly, the frame rates are high.
If it's a slideshow, the frame rates are low.