Quick qestion to the forum, does anyone know if FSX has native support for Ambient Occlusion ?

 

If it does, is it worth enabling it in Nvidia Control panel or Nvidia Inspector ?

 

Thanks, Buster.

Short and sweet. No.

OK, Cheers for the swift reply.

 

Buster.

A lot of aircraft and scenery modelers are baking ambient occlusioin into their models these days anyway, so it might look a bit overdone if it did work.

A lot of aircraft and scenery modelers are baking ambient occlusioin into their models these days anyway, so it might look a bit overdone if it did work.

 

Didn't even think about that! Do you mind elaborating just a tad, Bill?

I'm not Bill, but the process is relatively easy. Instead of making textures that are uniform in color all over the aircraft you paint in some darkened shadows in all the places where surfaces intersect or would cast shadows in some way (i.e. the wing roots, the bottom of the aircraft etc.). It makes an aircraft look much more realistic and thus less fake looking, because the FSX light shading simply isn't sufficient for that job. I suppose developers can also export the shading renders from their modelling program to generate an ambient occlusion layer for the paintkit. The lack of ambient occlusion is the reason way so many freeware aircraft and even some payware aircraft look so flat and plasticky.

 

Here is an example as an animated GIF. The very old Aerosoft Beaver looks pretty good at a first glance, but when you add some shading in the right places it immedidately looks more real.

 

 

Of course I only made that example by roughly painting the shading into the screenshot. It would look better if it were done properly with a paintkit and directly on the textures.

FSX doesn't have a real lighting engine that casts actual light sources in a way that would even make this possible. (taxi around a "lit" airport at night sometime - you'll notice your airplane stays totally dark) True ambient occlusion is calculated dynamicaly and can change with changes in the scene lighting.

Yep, what Ryan said. In the absence of true multi-point lighting, developers cheat a little and add static AO in the way Jigsaw showed.

Ambient Occlusion doesn't change with changes in the scenery lighting like the time of the day or the direction and color or the light source, and it doesn't need or use multiple light sources either.

 

This is how pure AO looks like:

 

 

"Light not affecting baked shading" - One can move the light source in every position, but the AO will still look exactly the same.

 

AO is exactly the opposite of a shadow dependent on the light direction/color/intensity: it's an approximation (and very rough) of what would be the one and true illumination method, which is the "Global Illumination", and many confuse AO with self-shadowing,which is instead just a sub-set of the general "shadowing" (objects casting shadows on themselves).

 

AO it's a different thing, and is related only to the object actual geometry and its relationship with the object objects geometry (but NOT shadows *casted* by other objects on it, that would be regular shadows).

 

To generate just AO, a non-directional light is used, and the result tends to be similar to what we see on an overcast day: a diffuse shadowing without directional shadows that are instead a signature of a light with its own precise direction, like the Sun at a specific time of the day. But as I've said, it's a very crude approximation, since in a real-world overcast day we would still have plenty of interactions with sky light scattering and colored objects bleeding into each other, which is far more complex than just AO.

 

A full complete rendering using a directional sun-like light source will include BOTH components: shadows coming from proper shadowing (which ARE changing depending on the light source direction/color/intensity) AND a separate component which is the AO. Any rendering program will let to separate those two components, which might be useful to get as separate elements, because one might want to just add AO to existing textures, to be used in an engine which DOES support regular shadowing so, it would be wrong to BOTH "bake" shadows in the textures AND render them on an engine that supports shadows casting so, base colors (A.K.A. "Albedo map") + AO are usually put together in the pre-rendered texture, that will get proper shadows in real-time, assuming the graphic engine doesn't also support real-time AO in the first place, in that case no AO would be needed to be baked either.

 

FSX, of course, has a limited lighting engine, which is tricky to work with because, while it DOES support shadowing and self-shadowing, the method used is very limited and shadows are rendered entirely different ways, some are just flat polygons over the terrain (airplane and building shadows), some are a bit better (airplane self-shadowing option or DX10 Self-shadowing VC), and some are just the result of a flat shading algorithm (different illumination depending on the sun position), and then there's the terrain itself, which uses an even different method, if shadows are turned on (lightmaps generated on the fly)

 

This means it's a bit of a mess for an FSX developer to decide what to use, because in some cases it would be best to bake BOTH AO and actual Shadows in the textures, sometimes it would be best to bake AO only, it really depends where that texture is going to be used. For example, textures for a VC should be ideally made in two versions: one with AO + Shadows, for DX9 users, and another with just AO, for DX10 users that will get real-time self-shadowing in the VC...

 

Of course, baking proper Shadows, will result in a static texture that is valid only for a specific time of day and view direction, which means textures will start looking wrong at some point, while AO is light independent, so it can be used more easily.

I did actually get this 'sort of' working a couple of months ago, although the result wasn't very good so I never pushed it further.

 

 

Anyway you can see here how the gear-bay gets darker/lighter as the gear extends/retracts. You can also see it on the flaps etc.

Has anyone got AO to work in FSX/DX10? If so, how?

 

I tried various combinations of AO settings in NVI but no luck so far.

Did you actually read this thread?

Did you actually read this thread?

Well - thanks for your wonderfully helpful comment - not. YES I did read it through - but it's confusing and contradictory.

 

#2 says it just can't be done - and further posts describing how it's imitated in paintkits (which I understand fully).

 

However - Jordi's comment (#10) indicates that it *can* (and shows a video) - but doesn't say whether it was in DX9 or DX10 mode, or how he got it "sort of" working.

 

If you read *my* comment, I'm referring specifically to DX10 preview mode.

However - Jordi's comment (#10) indicates that it *can* (and shows a video) - but doesn't say whether it was in DX9 or DX10 mode, or how he got it "sort of" working.

 

Yes it can be acheived *somehow*, but since Jordi is a developer (EnigmaSim), I'm pretty sure that his solution involves something more (shader hack or an extra module) than mere NVI settings.

 

I suggest just accepting that it can't be done (as implied by the majority of the replies in this thread) without more extensive interference into FSX' inner workings.

I suggest just accepting that it can't be done (as implied by the majority of the replies in this thread) without more extensive interference into FSX' inner workings.

Aaah ... OK, understood - thanks. I won't waste any more time trying then