Ground polygon layers

[John Young]

I've been trying out the new GP features in ADE1.6 and already I can see some really useful benefits, particularly with apron light splashes at night. I've included a screen shot that shows an over-sized ground polygon to illustrate a couple of points:



1. When I use a GP at layer 10, it covers any underlying runways, conventional taxiways and polygons. However a GP line used as a taxiway and layered higher stays above the grass. Is there any way please to force the custom grass under all the hard surfaces?

2. When I draw a taxiway with a GP line, the yellow dotted centre line is fine, but I don't get the option to orientate the Backing Texture so that joins in concrete slabs run at right angles to the taxiway edge. I can do this if I draw the taxiway as a polygon but then it's difficult to keep opposite edges parallel. Am I missing something here please?

The GP grass hides taxiway lighting. I saw the topic in the GP thread about cutting holes or using effects files, but it's a major downside to using this way of making grass. Is that something that could be overcome in a future development please?

I'm really wondering if this is the best way to make custom airfield grass and taxiways. Any advice would be appreciated.

John

 

[gadgets]

1. GP objects will always display above aprons/taxiways/runways. If you want the grass to display below, then you can't use a GP object. Use terrain polys instead - like your airport background and surrounding landclass.

2. Line backing is simply another line drawn below the line itself. You cannot control the positioning of the backing independently. Try drawing the line without backing and create a separate backing ploy.

3. Ground polys also cover stock lighting. The recently-introduced AFLT (which uses 3D models) can replace stock lighting and is not affected by ground polys.

Don

 

[John Young]

Thanks Don, I'm going to try a modified approach today. The beauty of the polygons covering the conventional taxiway links is that it enables a separate and buried "AFCAD" layer to be drawn more easily with the "plumbing method" to control AI aircraft with through parking. That's something I haven't done since my Airport For Windows days. AFLT should then provide the missing ingredient.

What surprised me in FSX is that with the SCASM code from my test GP polygons and lines present, the frame rate held up really well. I thought SCASM compatibility was ceased with FSX SP2. I know when I've tried one of my SCASM-built sceneries in FSX, the frame rate drops to 3 or 4 fps compared to perhaps 60 or 70 in FS9.

John

 

[gadgets]

The beauty of the polygons covering the conventional taxiway links is that it enables a separate and buried "AFCAD" layer to be drawn more easily with the "plumbing method" to control AI aircraft with through parking.

John, not quite sure how you are approaching this, but all my six airports use the "plumbing method" for drive-through parking and I did not have to resort to using ground polys to cover taxiway links.

I thought SCASM compatibility was ceased with FSX SP2. I know when I've tried one of my SCASM-built sceneries in FSX, the frame rate drops to 3 or 4 fps compared to perhaps 60 or 70 in FS9.

This is not SCASM per se but, rather, mostly BGL code with a few ASM instructions interspersed. The ASM code is available in a file names ADE_GP.asm in your ADE library.

 

[John Young]

I haven't got as far as setting up the AI yet, but I'm getting the hang of designing with the GP features and custom textures in ADE and the facility is really useful. I've not used the plumbing method for about 6 years now, but because some of the turns can be a bit messy, it was always a useful feature of Airport For Windows to be able to have the AI AFCAD layer buried. I'm not sure yet whether I will need to do that if all the taxiways are drawn as GPs, but I'll have a play with that a little down stream.

John

 

[gadgets]

Once again, its not clear what you are trying to accomplish. With the plumbing method, one set of taxiways is drawn with (visible) taxi-links while the other(s) with (invisible) taxi-links. I use taxi-links for arriving traffic. I suppress all center/edge lines in the vicinity of the aprons and draw lead-in/guide lines with GP lines. Covering your taxiways with ground polys seems like a lot of work and unnecessary.

There are others ways to eliminate the "spiderwebs" at corners and still have smooth taxiway centerlines. I discuss some of them in my tutorial "Adding Realism to Airports", available at http://stuff4fs.com

But, it's your airport ....

Don

 

[John Young]

Thanks Don, I'm trying to find an alternative way of producing ground scenery to conventional AFCADs placed over the top of Photo-tiles. I've been experimenting with the new ADE GP features to see if I can produce a custom look but without having to go to the expense of a photo-image or hand drawing the tiles myself. I'm getting there I think, but I still need to do a bit more work to get the appearance right. The whole of the ground layout is built with GP polygons and lines, using 4 or 5 key 2048 x 2048 ground textures (grass, aprons etc). I'll be planting 3-D trees over the wooded polygons. This is the FSX version, but I also want to convert the scenery for FS9 too (I've made the AI Phantoms for both versions in any case):



The technique produces nice quality at ground level:



I particularly like the ease at which floodlight spashes can be used with night textures:



I say "ease" because I had an initial problem that had to be overcome. I used an alpha channel around the night time splash to fade this out and a totally transparent alpha for the day texture. However I found that the night texture was adopting the day time alpha and that obliterated the lighting at night. Reversing the "problem" and putting the night-time alpha into the day time texture solved the problem. I don't know why, but it worked.

Since the elements are not linked together I can't use these as a conventional AFCAD to steer the AI traffic. The plumbing method is ideal for military airfields because of flight line through parking and the turning circles on the shelter aprons. Being able to bury an "under-laid" AFCAD has worked well in the past where SCASM code permitted that.

Two problems so far:

1. When they are switched on, ground shadows flicker like crazy. I have a new graphics card, but I tried the shadows at another of my airfields and they are stable.

2. When I first viewed the scenery at 2000ft, all of the ground polygons flickered badly across the whole airfield. I re-read the manual and followed the advice of lowering the flatten elevation a tad. That solved 90% of the problem but there's an area between the runway threshold and the first two shelters that I can't stop flickering. I've pushed the flatten out further but that didn't help. I haven't found out yet how to produce an "elevation stub", but maybe that's the answer.

If I can solve the flickering, I think it might work. I tested the frame rate with the first image and returned an average in excess of 200 fps, so plenty of scope for the rest of the build remains. I also flew some tight low level circuits to test for texture load stuttering and there wasn't a hint of it.

If you could suggest anything else relevant to this approach and to cure the flickering problem, that would certainly keep me on this track.

John

 

[GHD]

John,

I use xml aprons for all aprons and taxiways and use apron paths per the plumbing method. I use GP polys only for small ground marks such as stand markings and "NO ENTRY" signs, and GP lines for all taxi lines, H-S nodes etc. I use effects for taxiway edge lights and models for taxiway centre-line lights.

This method works well in both FSX and P3D V2.

 

[John Young]

George, when you say you use xml aprons and taxiways, how are those drawn and compiled please? Are you using Gmax xml polygons in some way, or are you hand coding? I notice that you have managed to get the concrete slabs of your apron at right angles to the apron edge.

John

 

[GHD]

I use ADE for everything. It is fortuitous that the apron jointa are parallel to the taxiway. The joints are always drawn parallel to the runway.

 

[gadgets]

Looks good, John. But, like George (yours looks great, George), I still don't see anything you can't do using ADE-generated aprons, taxiways and links.

I re-read the manual and followed the advice of lowering the flatten elevation a tad. That solved 90% of the problem but there's an area between the runway threshold and the first two shelters that I can't stop flickering.

With ground polys, your flatten and the airport should be at the same elevation. Otherwise, if your airport reference point is not on a runway, taxiway or apron, you may not see ground polys drawn on top of runways, taxiways or aprons. And, if your ARP is on a runway, taxiway or apron, the flatten being lower than the ARP elevation by more than a few millimeters could induce flickering.

Based on an issue reported a couple of days ago, earth's curvature may also be an issue in FSX/P3D. I'd recommend you compile with smaller (100m - 500m) groups - especially for FS9 where the polys are not broken up into 100m "chunks" by default.

I haven't found out yet how to produce an "elevation stub", but maybe that's the answer

Unlikely. In any case, if you haven't changed airport elevation from the default, a elevation stub is not needed. If you have, the need for a stub would be quite apparent since you'd see runway/taxiway/apron flattening above or below the surrounding "flattened" terrain.

Don

 

[scruffyduck]

ADE will automatically create an 'elevation stub for you if you use Tools > Change Airport Altitude. It will also make changes to things that have altitude like runways, starts and so on. It won't change terrain flattens however since it does not know if you want those changed.

 

[FlyingAxx]

ADE will automatically create an 'elevation stub for you if you use Tools > Change Airport Altitude. It will also make changes to things that have altitude like runways, starts and so on. It won't change terrain flattens however since it does not know if you want those changed.

What's about a checkbox to change all altitude vertices having the same level as the the runway?

 

[stevo]

Hi

I've been working with John on this project and have been trying to figure out what is causing the flicker and I think I have a reason but dont know why it does it. The ground line used as a 15m taxiways on their own are rock solid (as in no flicker at all) but as soon as a ground polygon is added everything flickers. Is this a know issue or a bug??

This is the first time weve tried to create an airfield layout using ADE with our own textures. I've previously done a similar thing using Gmax to build the taxiways and Arnos Model Converter X to place them in FSX and when doing it that way there is no flicker at all.

Stevo

 

[stevo]

Just to add to my post above....

Before xmas was the first time I installed ADE 1.60 (with the ground poly features) and as a test I did a small section of RAF Coltishall's taxiway using the custom line and custom poly features to test if it would be usable in this way. Which at the time it seemed to work perfectly, the lines and polygons where rock solid with no flickering of any sort.

Then jump to Johns issue above where now adding in a custom polygon seems to make everything flicker, remove the polygon the custom lines are stable again, which I couldnt understand why John was having the issue because I didnt come across anything like that while using it before xmas.

So I go back Coltishall which i havent recompiled since I did it last year just to check it wasnt flickering and as I thought it wasnt, so just out of interest I recompiled with the current version of ADE, the result was....

Before recompiling (this was last years ADE version) THe tarmac and concrete taxiway are custom lines, the apron next to the runway is a custom ground polygon and everything is stable from ground upto 5000ft

After recompiling (current version of ADE) you can see the massive amount of flicker, which seems to be caused by the large custom polygon, nothing else has been changed or altered apart from the version of ADE used


Now with the large custom polygon removed, leaving the custom lines, taxiways do not flicker


Is it possible a bug has slipped in??

Stevo

 

[gadgets]

I made several suggestions yesterday. have you tried them?

Don

 

[John Young]

Yes Don, prior to Stevo trying to resolve the problem I had tried:

- Changing the layer numbering (makes no difference)

- Placing default taxiways under the GP ones (makes no difference).

- Placing a very wide runway under the scenery (makes no difference)

- Lowering the flatten elevation by .25m (gives some improvement, but then the 3-D Gmax models float).

- "Changing" the airfield elevation back to default (it was already there) and setting the flatten to match (makes no difference).

- Deleting the large grass polygons (makes no difference).

- Compiling as a 50m group (gives a slight improvement, but the frame rate nose-dives to an unacceptable level).

- Viewing the converted file in FS9 in case it’s due to the Earth’s curvature in FSX (still flickers).

I also confirmed Stevo's findings yesterday. With no GP polygons present GP lines don't flicker, but as soon as the GP polygons are added back in the whole thing flickers. Note this is noticeable at an altitude of around 2000ft and above.

This morning I tried the simplest of tests to modify a default airport in FSX (Manston EGMH). I placed one GP line (red) at layer 40 and first tested that. It was rock stable.

I next added one GP polygon at layer 35 and another at layer 30. The whole thing flickers but it is not apparent until 2000ft and above, but above that altitude it is very pronounced:



Finally, I reduced the size of the polygons, just in case that's a factor, to less than the width of the runway, but still the flickering persists. I used the textures supplied with ADE and nothing we've made ourselves.

John

 

[John Young]

This mornings ADE update to 01.55.460.23619 has fixed the problem. Everything is now stable. Be interested to know what the bug was.

 

[scruffyduck]

1.55.460 is not a current version! Do you mean 1.60.5174? If so there is an update to the GP editor/compiler

 

[stevo]

Hi Jon

Whatever you did or changed in the last release has solved the flickering issue completely...thanks, eveything is now rock solid again no flickering at all.