how does underground lodding work?

[GoaSkin]

To create underpasses and models with surfaces beyond the ground levels that support the placement of props or the illustration of vehicles bethween ground level, you need to render in a way that vertex points with Z-coordinates less than zero are required.
When you export a model, normally everything that is in underground is flattened and replaced with a fake texture on the top that looks if there is something beyond the ground level. How can you export it in a way that it is usable for an unroofed tunnel or a ramp?
Even many modellers with much experience do not know how to do this.

[FromTheAshes]

Dunno how this works on underpasses, but when you for example want to create a underground mall (beside the fact that there are allready existing) you just create a simple LOT at exact ground level. You'll see everything under it.

[praiodan]

FTA, I guess this wasn't what GoaSkin was driving at because this would just cause what he wants to avoid, that you have only some kind of texture showing the underground.

In theory, it could work with just very tight custom LODs that cover also the model under ground. But I'm not completly sure about it as I never really modelled anything below Z=0 yet. Usually for that I would've done it like FTA says, because I guess with just ordinary LODs going below 0 you would have glitches between the model and the base texture.
So I'd say, the proof of the pudding is in the eating...

[GoaSkin]

Is it possibly easier to make the hard work to create the model completely on overground and then shift the vertex points (point by point in all 20 S3Ds) manually using iLive Reader down?

[FromTheAshes]

Tell me, do you want to create a TE underpass or just a building or garage or what under ground level?

[GoaSkin]

I want to create a functional underground railway station that has no roof on it's top - like a rectangular open tunnel part with trains with a railroad track and platforms in a height of -10 that shows the trains going along there and the props you set onto the platforms.

[cogeo]

The interior should be hollow for the props and the automata to be visible. Otherwise they will be obscured by the upper face of the LODshell. So the LODs should encompass the walls and the bottom (the track level). You can include the platforms too, or instead make them props.

[DebussyMan]

Not sure. But I think you can't place any props below 0. At least not with the LE.
Also, here's a test using "tight" LODs underground. As you can see, the base texture appears in the "hole" of the LOD.

[Jonathan]

I think you have to remove the texture using the reader.

[DebussyMan]

My guess is that the terrain would still show.

[GoaSkin]

For example, on the EL-to-subway ramp goes into underground. The grass is not shown there. There is a bug that filles the hole with grass when a building grows up beside but when you change the zoom, go into the pipe modus or do something else to force a re-illustration, it looks hollow again. What you show on the picture looks well. You are right, you cannot set a base texture on these models, except if you create one that is transparent on one side. The easiest way is to create a model that is exact field lengths large and broad.

Can you please explain how you have done this? Many people don't know that this is possible what's the reason why there isn't much stuff with traffic under ground level.

[cogeo]

NOB has made something similar. You have to lay water pipes under the station to show correctly (weird indeed). You can ask NOB or try to guess the shape of the LODs from the S3D models in the model file.
Try setting the IsGroundModel property on and off, also I don't know if this has to be a building or prop. Shades can prove a real PIA.

[GoaSkin]

I don't mean that it should be visible in underground mode but that after rendering there are negative Z-vertexes. But I may ask NOB. His sunken GLR pieces are like the same.