moving COG/focus point of a model

Hi Guys,

I was wondering if it is possible to move axis origin of a model somehow, not by editing it, but rather via xml (?). so that movement aroud axis (pitch, bank, yaw) and focus point from an external view will be slightly moved as I desire.

I have noticed, that moving focus point and rotation around axes is posible in "chase" view mode using the same combination of keys as is used to move eyepoint in VC.

thanks for ideas

majky

Are you speaking of the CG of the aircraft or the actual "origin" for aircraft behavior, or are you asking about a repositioning of reference point for the "camera" with which you are viewing the aircraft?

For the camera viewpoint there's information in the SDK about certain parameters in the aircraft config file that can be changed, individually for the cockpit cameras and the external ones. For moving the eyepoint base position there is an entry in aircraft.cfg in the [views] section that looks like:

eyepoint = -0.55, -0.85, 3.20 //Longitudinal, Lateral, Vertical (feet)

It is obviously different for each aircraft, but you can change the numbers and move the view around.

And there are sections in the aircraft.cfg that can change aircraft behavior in many ways, in sections such as:

[airplane_geometry]

[contact_points]

[weight_and_balance]

[fuel]

[flight_tuning]

Also there are sections in the aircraft.cfg for [CameraDefinition.xxx] and there is also a cameras.cfg file where you can change values for additional camera types.

All these .cfg files are in: C:\Users\YourUserName\AppData\Roaming\Microsoft\FSX on Windows 7. It might be a tad different in Win 10, but I don't have that.

All of these are described in the SDK. If the above aren't what you need, then you'll need to describe what it is you actually want to accomplish.

no. I dont mean changing behavior (controls efectivnes, MOI, etc).

I mean shifting model´s axis origin without editing the model itself..

Perhaps 'Radius editor' from the FS Developer site is what you are looking for.

https://www.fsdeveloper.com/wiki/index.php?title=RADItor

I mean shifting model´s axis origin without editing the model itself.

And what is that intended to achieve? What is the problem you're trying to solve, the reason for doing this? What is the reason that you want to be "shifting model´s axis origin" in the first place? Is it the appearance of something, or a change in viewing capabilities, or...???

Or maybe Lab's suggestion does the job for you.

no. I dont mean changing behavior (controls efectivnes, MOI, etc).

I mean shifting model´s axis origin without editing the model itself..

Sounds like you are trying to setup different camera angles. Are you doing this for screenshots of your aircraft in an outside view?

Tie goes to the runner, Larry! ;) Feets, don't fail me now!

no, 'Radius editor' didnt do "the trick" :/

what Im trying to achieve is to set CoG of an empty machine into correct place. ie default Merlin has it wrong I belive (red "as is", green "should be")

Still curious as to "why"? In moving the CoG, what will that accomplish for you? It's always best to state what you are trying to do and why you are trying to do it.

Are you trying to move the aircraft more towards the red line I've drawn for screenshots?

it will make me more happy and the sim more enjoyable ;)

its no big deal, I was just wondering if it is possible..

it will make me more happy and the sim more enjoyable ;)

its no big deal, I was just wondering if it is possible..

ok, but IF you did actually move the CoG, your flight dynamics would go to "hell in a handbasket"!

No I dindnt. and I dont intend to. Its really about axis origin in the model rather than CoG.

..and answer to your question (with the red line in picture) is yes :)

No I dindnt. and I dont intend to. Its really about axis origin in the model rather than CoG.

..and answer to your question (with the red line in picture) is yes :)

Try using "Locked Spot" view. Much easier to adjust the image the way you want.

If you're trying to move the reference point of the 3D .mdl it appears this tool can do it for you:

http://www.flightsim.com/vbfs/fslib.php?do=search&fname=model_slider.zip

I played with it and here's the difference in MCX:

I haven't flown the aircraft since, I worry this might affect everything in the aircraft.cfg that's defined as a relative position from the datum. I don't know if the "datum" is actually the reference point of the .mdl however, I've adjusted positions for this & that in the aircraft.cfg a million times but I've never messed with the reference point in the .mdl. Good luck, and make a backup, lol.

EDIT: That appears to screw everything up. The VC would obviously need to be moved too which could be done but note the position of the nav lights, I'm thinking everything in the aircraft.cfg would need to be adjusted.

yes! It will absolutly mess up everything what is defined as a point (engines, lights, contact points...etc) in aircraft.cfg file. at least in X and Z (default Merlin). but I ll give it a try anyway... :)

on a secont thought, If I will know exactly how much would I move in a certain axe, I will be able to adjust points quickly. either just the reference point or single points individualy.

so I gave it a quick try and let me say: Thank you, mr. Robinson :) this is just what I was looking for.

exterior model works perfectly, aircraft.cfg corrected within 1minute via adjusting reference point if knowing exact values.

but still facing troubles with the crew :( need to check on that little more....

I didn't try it but couldn't you just use the tool to make the exact same correction on the interior model too?

So were you able to make all the adjustments in the acft.cfg just by changing:

reference_datum_position = x, x, x

?

sorry, I put it wrong. I ment interior of external model (the crew). VC works fine if making the same correction as with exterior model..

exactly, just X and Z adjustment in "reference_datum_position"

default was:

reference_datum_position = 30.5 , 0.0 , -3.0 [Feet]

now is:

reference_datum_position = 32.1 , 0.0 , -5.2 [Feet]

(I moved the axis origin -0,5m aft and 0,7m up)

To 'move' the 'viewpoint' (of pilot's head (eyes)) you adjust the x,y,z in (Views) section of aircraft cfg. The (views) section relates specifically to the VC 'view'. So adjust the values, reload the ac while in VC view, check view, and repeat until you get it where it 'should' be. SAVE the aircraft cfg after each adjust. Reloading ac produces the result of adjustment(s).

Chuck B

Napamule

The (views) section relates specifically to the VC 'view'.

Not true sir. It applies to the pilot's view whatever type of cockpit you are using.

John

so to conclude things up:

the "model_slider" is what I was looking for. it works pretty well except the crew models.

I contacted the author, Mr Igami, asking questions about crew "messing up" and he was surprised that it worked with external model too, because the sw was made mainly to "align" VC with exterior model/eyepoint position.

As of now he does not intend to fix the "crew issue" in the sw

majky