AI Models, Question from a new starter

[Pacman]

I have been building FSDS aircraft for some time but never get the detail I would like. A friend saw some of my work and said they would make good AI models. So here I am.

I would like to know the following if possible.

1. What is a good poly count for an AI? Is there a maximum figure, depending on model of course.
2. Do you complete all the model animatios as if it were a normal model?
3. LOD models, how many and how does the numbering relate to view distance etc. Are ther any rules for this?
4. Am I right in saying you create Mipmaps for the textures to work the same way as LOD's?

Sorry to ask the basics, but I am sure some kind person will take the time to explain.

Thanks

Pete

[MIKE JG]

Pete, welcome to our forums!

Before we answer your excellent questions, read these two links from AI Aardvark:

http://home.sprynet.com/~drawlins/AI_ai ... craft.html

http://www.ai-aardvark.com/modeling/LOD ... a_LOD.html

These guys sorta wrote the rules on AI modeling for FS9. Those two links, even though they are written from a Gmax perspective, still apply to FSDS modeling. I think after reading through those two links, most of your questions will have been answered.

Whatever questions you have left after reading through that, fire away, we'll be happy to answer.

[Pacman]

Mike,

Thanks for that, it should keep me going for a bit. Still not sure on the textures though, do I use mipmaps?

Another question for later on is how do I animate the aircraft? i.e make the wheels retract when taking off etc. and flaps? is this done with .xml scripts of in the traffic program. Not even looked at that yet.

Pete

[MIKE JG]

Mipmaps are a lively topic around here lately. I've always used them on my textures for both aircraft and scenery and have never had any issues. Some people have graphics cards that don't like mipmaps. I believe that we've (Military AI Works) have finally settled on a policy of including mipmaps with all of our textures from now on. So yes you probably should use them.

As far as the animations go, there are a couple documents that explain a lot of animation stuff that you won't necessarily find other places. Those docs are the Gmax and MakeMdl SDK's for FS2004 from Microsoft.

Here is a link to all the FS9 SDK's. The MakeMdl and Gmax ones that you want to download and read are about half way down the list. There are Word docs included in each SDK download that you'll want to read.

http://www.fsdeveloper.com/forum/downlo ... =cat&id=10

I know, I know, I'm asking you to read even more information. But it is important information, especially the bits about material names, part names and animations.

MakeMdl will recognize certain part names and automatically apply the correct animation to them. For example, for any model, AI or otherwise, if I name the landing gear legs, "c_gear", "l_gear" and "r_gear"....that's all I have to do to animate the landing gear for that model. MakeMdl will do the rest and then I can adjust the actual retract/extend time cycle with an entry in the Aircraft.cfg file. I can also animate the wheels using the correct name. Otherwise you have to apply a custom animation to these parts which is a longer, more involved process.

For AI models, these "stock" animations are automatically controlled by the AI engine. Some modelers don't like the way those animations run and will create custom animations for the gear (for example) based on an XML script. So that is also possible.

One thing we've learned to do with our models here over the last 5 years is to base the flaps/slats on XML scripts instead of relying on the FS9 engine. That allows us to set them for takeoff and landing based on speed and light parameters. Gives a much more realistic look to the model.

So getting the part names correct is VERY VERY important. The only way you know what to name certain things is to study those two SKD documents.

As far as writing the actual XML scripts, we have a nice knowledge base of XML coding that can be used on AI models. So we can easily help with that.



All the orange covers, remove before flight banners, wheel chocks, etc from this model are XML based. We use a certain script to make them show up only based on certain parameters. On non propeller AI models, we can simply use the navigation lights to trigger whether these parts show up or not. Through much hair pulling by Rysiek Winnawer, (C-17, An-2, A-10 models) he figured out that for prop models, the normal XML scripts won't work. So he came up with a different script that makes these parts show/no show based on something else.

It's this kind of knowledge that collectively, we can share with modelers who are just getting started. Otherwise that sort of thing might take you weeks of hair pulling to figure out on your own.

We're certainly here to help if people want it.

I'm really surprised that more people don't give modeling a try, if I can do it, anyone can. Just takes time, patience and persistence.

[MIKE JG]

I should mention that simply creating the 3D model of an aircraft is only part of the process. It still has to have textures applied to it and then has to be tweaked to fly correctly inside of the sim.

Textures themselves are a learned art form, simple shading and lighting tricks can go a long way towards improving the look of the mode and making up for shortfalls in the actual 3D design.

Then there is the whole flight dynamics part. That part is the least well understood part of creating an AI model. Fortunately we are blessed to have probably the premier AI dynamics expert in the world among our ranks here. That would be Michael MacIntyre and he has done the flight dynamics on 99% of all MAIW models released thus far.

This is what is referred to as the model's FDE (flight dynamics engine). This is the combination of the Aircraft.cfg and .AIR file. These two files contain parameters that tell the sim how to make the aircraft operate in game. Since AI models are basically moving scenery, they do not behave like a user model and therefore are not programmed to fly like a regular model. If you want to see what I mean, take an AI model of your choice, make it selectable in your FS9 menu, then try flying it around like you would a normal user model. You will find that the AI model is very sluggish when compared to a normal model. Yet when used as an AI model in game, it performs as it should.

I know just enough about the process to write this. Beyond that, the knowledge gets pretty specialized. Fortunately for us, Mike M. is very good at what he does and makes these AI models fly in game like their real world counterparts. This is a time consuming process that requires a lot of file editing, reloading of the sim and checking how the changes you just made affect the model's behaivor.

So......... there is a lot more to it than just making the 3D model. Fortunately we have "experts" in those other critical areas that can help.

Unfortunately most people only recognize the actual modeler who make the 3D model. The other guys who paint and tweak the model's behavior get very little love.

Be sure to thank all these guys when we release new models over the next couple months. There are plenty of new ones coming.

[james84]

Welcome Pete!
Mike, great model indeed!

[shaggy22]

I'm really surprised that more people don't give modeling a try, if I can do it, anyone can. Just takes time, patience and persistence.

Precisely what i don't have!!!

[Pacman]

Thanks to everybody for the reply so far, I am sure I will have some more questions later on.

I am currently making models with animations, panels and textures that work fine in both FS9 and some FSX. This is what has prompted me to try AI as they are not as involved. I still struggle with the VC in a normal flyable aircraft and doing everything on my own, it takes an age.

The idea came about while looking through some old projects that I had started and left for one reason or another (hit a brick wall during design when I could not do something). When looking at them they are 70% complete externally and most only need cockpits and VC's adding and some textures. These of course do not need to be so detailed in AI.

My question about animations was based on when they are used as AI, as I have seen some take off and retract gear, raise flaps etc. I was not sure how this bit is achieved, but your reply has gone some way to answer this.

Mipmaps are new to me, I have seen the option but never used them and was not sure if they are to be used the same way as scenery - again, now I have the answer.
LOD's again, I know what they are but did not know when to use, if at all - again the web site link answers that question.

Many thanks for the support so far. I am not sure where to begin now, convert an existing model or start something new? May have a go at converting some existing planes for now, I will let you know how they pan out.

I do still have an on going project of a flyable aircraft that is awaiting more detail when I can get back to the airfield to take some more pics.

Thanks again

Pete

[Weescotty]

9 times out of 10 starting a new one is usually the best way to go,

Going through all the parts one by one and seeing if you can reduce the polys can take more time than just creating newer lower poly parts.

[Pacman]

I also think I will start a new model from scratch as having reviewed some of my existing models they are all over 10,000 polys already.

I am still not sure what figure I should be aiming for. Some aircraft I have been looking at must be well over 2,000 polys to be as detailed as they are.

Can anybody give me some kind of idea what I should be aiming for as a maximum, for say a single seat jet such as an F15 or Eurofighter size. And also for say a Herc or 747.

Thanks again in advance for the help.

Pete

[sr01]

Pete
Thanks for asking the questions and Mike ,Thanks for generously answering clearly and providing the URLS !!

[MIKE JG]

Pete a rough number to shoot for is 3000-4000 polys for your LOD1 model. However this isn't as critical as it used to be during the early days of FS9. Processors and graphics cards continue to evolve and we're finding we can get away with more and more polys these days as opposed to the old days.

The key is the use of the LODs. By about the third LOD you can really start saving on the polygons with more and more simple parts. Most models have from 6-10 LODs.

But the real FPS killer are the textures. You will never catch your machine slowly filling in 3D models. They seem to always be there in their bare bones material color (usually gray). You will however, under high percentage AI situations, find your computer slowing to fill in the individual textures, sometimes one at a time. So the fewer textures we use for each model, ideally just one, the better. We have however been getting a bit carried away lately by having up to 5 different textures for a single AI model. Usually there is just the one single main texture, usually a 1024x1024 sheet compressed to DXT3 format. Then sometimes for things like weapons or propellers or even canopies, there may be an additional small texture, usually 512x512 for the weapons, 256x256 for propellers and so on. Also any model can have a light map texture which adds details for night time conditions.

[Pacman]

Mike,

Many thanks for the reply, 3-4000 sounds a better number to me. Not sure where I got the 2000 from, but I think anybody would struggle to get a decent plane from that.

As for your comments on textures, I try where possible to do that anyway, even on my scenery.

The LOD info is most important to know as this is new to me.

Thanks again for the info.


Pete

[Greg]

Around 2000 was the target in the early AI Aardvark days, but that's a looooong time ago

[Weescotty]

Around 2000 was the target in the early AI Aardvark days, but that's a looooong time ago

Yeah but it's a lot easier to get around that number on a civvy airliner.

Next to impossible on a mil aicraft because of its overall shape. Lots of inny outy curvy bits.

For helis you would struggle to get under 3000 - 4000 polys.

[MIKE JG]

Not to mention all the weapons loads hanging off the models.

[Pacman]

Good to hear its not just me having to struggle with poly count. I only do military stuff, not into airliners so I guess they are going to end up near to the 4000 mark.

Good, as long as I know what to aim for.

Thanks again to all who replied.

Pete

[MIKE JG]

Pete, this thread: http://www.militaryaiworks.com/newforum ... =10&t=1206 shows what AI models are already available if you are curious.

I need to add some models to it but it's pretty accurate.

[andras1]

Hi Mike,

in one the post above you wrote about the XML knowledge base that you are ready to share. I have made two quite reasonable helicopter models - a twin two twelve and a jetranger/Kiowa. I got stuck because I did not get the rotor animations rights. Both helis use skids so they do have to take off before the start taxiing. I tried to connect the rotor movement to the nav lights and this is where after a while I got stuck. I would be grateful for some support - or some ideas how to tackle the rotor animation.

Andras

[MIKE JG]

For the rotor animation, there is a standard way to do that with part names and then there might be another way to do that with XML based animations.

The standard way also utilizes a rotor disc (separate part) that can be textured to look like a set of blurred rotor blades when they are spinning at high speed.

If you are trying to do it with XML scripts, I suppose you could try Tick18 animation and then make the part conditionally visible based off of the beacon light.

The XML way is probably a bit more difficult to work with. The standard way is pretty straight forward.

Which do you want to try?