EFM vs PFM

I thought that I understood the DCS product terms untill now, but Ells just draw me attention that I was a bit (more) away.

So, by EFM (External Flight Model) I was initially understood that code that it will be injected in DCS World (base engine) in order to make available (visible) a plane even somebody does not have it but want to join to a mixt flying formation for example. Other beeing said is how somebody not owning that module is able to see the AI/Human piloting the plane from external view. It just not needed to have all feedback fellings but only visuals.

But I was wrong, EFM is the flight dynamic general available even you own or not a 3rd party module. "External" comes from out of ED offices let's say. To cite ED:

"External Flight Model (EFM). Used by our partner developers, the EFM uses only a part of PFM - rigid body physics and contact model. What forces and moments are applied to this rigid body from aerodynamics and any other sources except the contact forces is up to EFM developer."

Does my writings makes sense? Does anybody understood the same as me?

Next question is: how close EFM can be to PFM while using only a part of it? Maybe this is retoric and we have to test by oursleves, however I have to admit that I am extremly curious.

EFM does not define anything other than a minimum (rigid body physics and contact model). Beyond that, it could include much more or nothing else and it would still be EFM.

You pin-pointed a hot spot... could be all or nothing... it's up to dev... and marketing confusing.

You pin-pointed a hot spot... could be all or nothing... it's up to dev... and marketing confusing.

Yup, market gets confused by a reduction in ambiguity. :D

You've been given an explanation of the minimum included in an EFM.

Previously you did not have that.

If you want to know more: ask the developer in question.

What I don't get is the distinction between EFM and all-what-ED-can-do. For me, it sounds like a technical term: EFM is like an API where 3rd parties can "plug in" at pre-defined points their own logic. Probably something like a "skeleton" that defines the bare minimum that a FM has to provide.

ED on the other hand is not bound to that API - they can fiddle around with all internals as they like.

I would think, if someone really would want to make a "DCS: Tie Fighter", the EFM would be probably not suited for new engine types like "Impulse Drive" or even "Warp Drive". But ED could (or would have to extend the EFM API to allow 3rd parties to use sim data that have not been thought of before at all).

However, the terms SFM/AFM/PFM describe not HOW the FM is implemented, but WHAT of it is implemented. They describe different qualities.

So, from a customer perspective, if a FM is EFM or not is irrelevant and should be avoided, imo...

So, from a customer perspective, if a FM is EFM or not is irrelevant and should be avoided, imo...

Agreed. :thumbup:

I think EFM is just another way to say that the FM has been programmed outside of ED, I am not sure how DCS Labeled products might be sold, but it might be good for someone that might not be up on all things DCS to have an easy reference point to see that an aircraft isnt made by ED.

 

I think an example of this is why we have these new descriptions, or one of the reasons. The fact that AFM became the go to term for many Flight Sim creators out there, but that doesnt mean they are created equal. Same here... If a 3rd Party says that the have an EFM at AFM level, you know right of that it is first and foremost an externally created Flight Model, and that it may or may not be equal to what ED calls a AFM. Of course this is not to say a 3rd party AFM wouldnt be as good as ED's AFM... just that its possible that its different depending on the info and coding done.

 

Hope that made even a little bit of sense :)

I see your point, but I disagree. Imo the terms are meant to describe a quality level but "EFM" isn't one. And to be honest, the distinction of "made by ED" and "made by someone else" is not (up today) and should not be a sign of quality either.

In a way, EFM does describe a quality in the fact that it probably hasnt gone through the same checks by the ED FM team.... for example, the RRG FMs are being run through Yo-Yo, in some cases created by Yo-Yo... therefore they are not EFM. (And again, I am not saying that anyone using EFM means its a lower quality, but at the same time, it distinguishes between ED made/quality control or not)

I disagree, as long as they are using the api provided by ED, it is EFM. No matter if Yo-Yo cheked it, or not.

Well that is based on what? We really dont know what the 3rd Parties have access to, chances are its well beyond what we see in public APIs... and sorry, RRG FMs are highly unlikely to be classified EFM... but I could be wrong.

I could be asking the same question, if we don't know what 3rd parties are using, why are you saying it isn't EFM?

And that's the reason I used the IF statement. If they are using the available api, then it is EFM, because that's what the EFM label means. It says very litle about the model fidelity.

If they don't, then it isn't EFM.

Stating EFM, is according with definition an subset of PFM:

"Used by our partner developers, the EFM uses only a part of PFM "

This is clear that it starts at 0 and ends at 90% while PFM ends 100% (generic numbers). How close the 3rd party devs will be to their maximum 90% fidelity, well, only they know. What means that 10% difference, well ,only ED knows :D.

VEAO says about Hawk: "As such our aircraft will have EFM (up to PFM standards) and ASM for the internals/cockpit" . This statement is according with their initial announcement, first SFM and after AFM ... now close to PFM. So, as Sithspawn mentioned, EFM must be followed by SFM/AFM/AFM+/almost PFM :D as it alone means only that is 3rd party.

Anyway, I do hope this thread will clarify to some of us the difference of the new marketing terminology.

"VEAO says about Hawk: "As such our aircraft will have EFM (up to PFM standards) and ASM for the internals/cockpit" . This statement is according with their initial announcement, first SFM and after AFM ... now close to PFM. So, as Sithspawn mentioned, EFM must be followed by SFM/AFM/AFM+/almost PFM as it alone means only that is 3rd party."

Dunno about the "almost/ close to PFM" factor... seems if it isn't 100% PFM, it should be AFM+ by default

?

"VEAO says about Hawk: "As such our aircraft will have EFM (up to PFM standards) and ASM for the internals/cockpit" . This statement is according with their initial announcement, first SFM and after AFM ... now close to PFM. So, as Sithspawn mentioned, EFM must be followed by SFM/AFM/AFM+/almost PFM as it alone means only that is 3rd party."

 

 

 

Dunno about the "almost/ close to PFM" factor... seems if it isn't 100% PFM, it should be AFM+ by default

 

?

I don't think any of these are really a hard line. They seem to be more of an internal classification, encompassing a range of possibilities.

An EFM that is close to a PFM most probably means, "we don't know exactly how ED got the A-10C to fly like an A-10C, but we are pretty sure that our method reproduces nearly the same results."

ED on the other hand is not bound to that API - they can fiddle around with all internals as they like.

No, they're not, but there's not reason for them not to use it AFAIK. The EFM is an API that connects an external FM engine to the DCS engine that displays your vehicle. The API also provides for collisions and some other things, but the basic forces acting on the vehicle are computed by the 3rd parties FM engine, which is why ...

I would think, if someone really would want to make a "DCS: Tie Fighter", the EFM would be probably not suited for new engine types like "Impulse Drive" or even "Warp Drive".

A third party could absolutely do this. But then, ED doesn't simulate altitudes above 100km, so ;)

So, from a customer perspective, if a FM is EFM or not is irrelevant and should be avoided, imo...

You mean discussion of whether it is an EFM or not should be avoided, yes?

EFM vs PFM

Wow you are confusing yourselfs... ;)

A little history might clarify some things:

Ten years ago ED released a game called Lock On where the player could fly six different airplanes. All the planes used a common flight model code that ED dubbed _Survey_ Flight Model. The users could add new airplanes to the game and fly them by adding the visual 3D model and adding a table with the aerodynamic coefficients of the airplane into a plain text file within the game files. The flight model did only simulate aerodynamic effects and not physical ones (I believe) like momentum.

Then they made new flight model code for a new airplane (Su-25T) that where specifically coded for only simulating one aircraft (the Frogfoot) and could not be changed by anyone outside of ED to simulate any other aircraft. This new code also included physics modeling. They dubbed this system the Advanced Flight Model to differentiate it from the earlier flight models. They eventually made a new aircraft with a very different modeling (Ka-50) and after that a new aircraft (A-10C), again different from the one before.

Some years went and ED decided they wanted to have third party developers make aircrafts for their new product DCS:World (that wasn't SFM-models). Instead of having the third parties use their existing flight models (like in FSX, X-Plane and other games) they went with the idea of having the third parties coding their own flight models. This opened up the possibilities a lot for the third parties, firstly not being restricted in what to simulate (zeppeliners, gyro copters, Tie Fighters), and also free to use any available flight modeling library (like rotorlib). Problem was that it now takes years for the third parties to develop for this platform. ED included physics modeling (gravity, momentum etc) and collision modeling, so the third parties wouldn't need to code that too. This is probably what Wags is referring to when he wrote "part of the PFM is in the EFM". All aerodynamic effects are still up to the third party to make.

PFM = marketing speak.

Edit: sniped

Third parties don't need to spend years to code their FM. They can pick up any FM engine that's out there and free (eg. jbsim) and construct a model that is as simple as the SFM or as complex as the PFM.

As for marketing speak, sure, but it does inform you - the PFM is both the flight physics package and the flight system physics package (electrical, hydraulic, etc).

No, they're not, but there's not reason for them not to use it AFAIK. The EFM is an API that connects an external FM engine to the DCS engine that displays your vehicle. The API also provides for collisions and some other things, but the basic forces acting on the vehicle are computed by the 3rd parties FM engine, which is why ...

Sure, ED will surely take advantage of their existing API if they can. That's the point of an API, to provide ready-to-use solutions for known problems. But if an aircraft needs something special, that is not yet available via the EFM API, then at least ED has the means to work around it (i.e. just extend the EFM API to match their needs).

A third party could absolutely do this. But then, ED doesn't simulate altitudes above 100km, so ;)

And such special needs could probably be "new methods to keep an aircraft aloft" :o). I remember some video where ED (Yo-Yo in the RRG campaign?) explained how each aircraft they developed so far had at least something new. Ka-50: coax rotor, P-51: propeller, etc. This is what I meant. The EFM API now might provide for propeller driven aircrafts, for coax rotor helos, but maybe not for ... dunno, hot air balloons (effects of expanding balloon hull depending on the temperature -> drag -> blablabla, etc. or effects of the sun heating up the balloon even more the hotter the air gets as the hull expands ... no clue really, just a silly example ... :o).

You mean discussion of whether it is an EFM or not should be avoided, yes?

I think, the term "EFM" alone tells us customers nothing - it always needs to be seen in conjunction with the true quality label SFM/AFM/PFM. Therefore it can be omitted ... should be (allowed to be) omitted to avoid confusion, when it comes to advertising new 3rd party products.

But calling a 3rd Party FM a PFM may not be completely truthful in terms of it being equal to what ED classifies a PFM, the label EFM along with PFM (or SFM, AFM) lets you know that its a 3rd Party designed FM and it may or may not be equal to ED's offering.

There are no hard criteria of what a PFM has to include that I know of (or that were communicated by Wags) and therefore a "lazy" PFM (still better than a AFM+) could be probably of lesser quality than an "EFM up to par with PFM". At least this is how I interprete Ells when he claims that this will be the case for the Hawk.

And that it is a genuine ED product or a 3rd party product (together with the subjective expectations regarding the quality of their respective products) should be quite obvious when one looks at the company's logo. :o)