FSX Any way of creating an underpass/tunnel in ADEX

connomar

Resource contributor
#1
Me again,

The project I am working on has many vehicle tunnels to allow the service vehicles easy access across the field. I have tried every permutation of creating a Polygon and setting it to Airport Background Flatten and all the other settings. I have set two of the vertices to be 20 feet lower than the airport altitude, but I am getting absolutely nothing.

Right now, just having the road disappear into the ground is sufficient. Icing on the cake would be allowing the road to travel through the tunnel, but since it's actually just meant to be a slope to a dead end, no chance.

I wonder if you wonderful people come up with an answer, if I could drop a model into the hole so I can create a realistic looking entrance. More icing I know.

Any thoughts?

Thanks
Martin
 

Pyscen

Resource contributor
#2
Hello,...

Just wondering,... have you tried breaking up the flatten into separate flattens? Leaving the area with the tunnel unflatten so to speak? Just a suggestion,.. I'm sure others might have a better suggestion or idea on how to handle this ;).
 

connomar

Resource contributor
#3
Hello,...

Just wondering,... have you tried breaking up the flatten into separate flattens? Leaving the area with the tunnel unflatten so to speak? Just a suggestion,.. I'm sure others might have a better suggestion or idea on how to handle this ;).
Do you mean that I would drop the altitude of the airport by 20 feet, then leave a hole for my tunnel in an overall flatten?
 

Pyscen

Resource contributor
#4
Hello

not exactly,... you would have 2 flattens on the different sides of the tunnel,... the area of the tunnel would have multiple vertices or polygons that would blend into the flatten areas or match up with the 2 flattens. Though I'm not sure the vehicles can travel through a unflatten,... someone might need to correct me on this... I haven't tried it yet myself.
 

connomar

Resource contributor
#5
Hello

not exactly,... you would have 2 flattens on the different sides of the tunnel,... the area of the tunnel would have multiple vertices or polygons that would blend into the flatten areas or match up with the 2 flattens. Though I'm not sure the vehicles can travel through a unflatten,... someone might need to correct me on this... I haven't tried it yet myself.
I'll try it, sounds like an interesting idea. Thanks for your thoughts.
 

gadgets

Resource contributor
#6
There is no way to model a tunnel/underpass using terrain. (Terrain can only be at one elevation.) However, you could use sloping flattens to create a suitable depression, run your roadway through the depression (it will follow the terrain) and mould a cap/bridge across the top with gMax (or whatever).

If (portions of) the top of the bridge are to match the terrain, then the model must be for FS9. Place a copy of the terrain texture and all its seasonal variations in your texture folder and edit the model's .asm file to select the correct version of the texture as the seasons change.

Unfortunately, the seasonal changes no longer work in P3D v2.4, since LM has eliminated support for the required legacy (i.e., .asm) technology. But, if you pick a season ...

For an example of the end result, see the ammunition bunkers in my CYQQ.

Alternately, you could create a bigger depression and fill the whole thing with a modelled tunnel.
Don

EDIT: If you plan to place the tunnel under a runway or taxiway, be aware that runways and taxiways automatically flatten immediately-surrounding terrain to their level, So, the runway/taxiway may undo all your hard work. Suggest you do some simple experimentation first.
 

connomar

Resource contributor
#7
There is no way to model a tunnel/underpass using terrain. (Terrain can only be at one elevation.) However, you could use sloping flattens to create a suitable depression, run your roadway through the depression (it will follow the terrain) and mould a cap/bridge across the top with gMax (or whatever).

If (portions of) the top of the bridge are to match the terrain, then the model must be for FS9. Place a copy of the terrain texture and all its seasonal variations in your texture folder and edit the model's .asm file to select the correct version of the texture as the seasons change.

Unfortunately, the seasonal changes no longer work in P3D v2.4, since LM has eliminated support for the required legacy (i.e., .asm) technology. But, if you pick a season ...

For an example of the end result, see the ammunition bunkers in my CYQQ.

Alternately, you could create a bigger depression and fill the whole thing with a modelled tunnel.
Don

EDIT: If you plan to place the tunnel under a runway or taxiway, be aware that runways and taxiways automatically flatten immediately-surrounding terrain to their level, So, the runway/taxiway may undo all your hard work. Suggest you do some simple experimentation first.
Thanks Don, I like the idea of creating a depression and dropping a tunnel model into it. I've never looked at the ASM files, I've been pampered by your GP code in ADEX.:)

If the flatten is comprised of one long poly rectangle with 6 pairs of vertices, and the runways run over it, would you expect the runway flattening to wipe out the whole of my flatten, or only the bit within its perimeter?
 

connomar

Resource contributor
#9
Ok, after some testing, I've abandoned the idea. The runways and taxiways appear to create a flatten of around 120 feet around them, and since my tunnels are within that perimeter, I can never dig it out. I create a tunnel model and buried it, but one could only see the side walls where the were proud of the ground level.

Also found that flattens don't seem to have a defined gradient, and the bottom of a flatten seems to follow the original pre flatten topology, minus the depth of the custom flatten. e.g. If KMSP airport is set to 841 feet ASL, but the original terrain was hilly and variable from 800 to 841, those variations would be reflected in the hole one wanted to dig in the ground. I need a trench setting.
 
#14
With trial and error. :rolleyes:

Look at this : http://www.fsdeveloper.com/forum/threads/my-tunnel-jumping-up.432788/

Tunnels are from the ORBX scenery.

Train is from 3dwarehouse.sketchup and format with MCX.

And the original Scenery is from Andrew's Airports of Norway,ENVA is up-dated by me.

Jan
Is there a way to control how steep the drop off is? Mine always seem to have a consistent "buffer" and slope when placing flatten exclude autogen with different heights right next to each other.
 

tgibson

Resource contributor
#15
I think the minimum distance for elevation changes is the distance between mesh vertexes. I don't think you can get more control than that.
 
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