Hello and welcome to Part 5 in my series of tutorials on Overlay Editor.

In this tutorial we are going to look at an essential part of Overlay Editor, one that isn't always used but one that should always be included in virtually created scenery; that being the mysterious 'Exclusion Zone.'

So What Exactly Is An Exclusion Zone?

Well, as you're no doubt aware, there are many X-Plane sceneries available which enhance the look of the default X-Plane terrain. These include regional, country and world improvements and come in both freeware and payware guises. These enhancements really do make a tremendous difference to the often sparse world of X-Plane, but they do have one caveat...they tend to invade your workspace. If that space happens to be your custom scenery, then sorry, you'll just have to make room for that new industrial estate!

Let me give you an example. One of the most impressive scenery enhancements an X-Plane user can have (apart from HD Mesh) is the World2XPlane add-on which uses Open Street Map (OSM) data to populate a particular area. These areas include most of Europe and the US and are available to download at the World2XPlane web site.

As mentioned above though, as much as I consider World2XPlane a must have add-on, it does on occasion like to 'paint' or rather, intrude into your work area and because of this, this is where our wonderful exclusion zones come into play!

Upon opening Overlay Editor and navigating to the library pane (right hand panel) we can search for available libraries. By default, the Exclusions library is included with X-Plane and once located, you'll see that it contains eight types of exclusion zones, each one performing a particular function (Figure 1).

Figure 1

When creating a new scenery, I've found that adding exclusions to your area is a good starting point. I would suggest a minimum of one object and one forest exclusion zone. In the example below (Figure 2), you can see that we have created a single object exclusion box which will act as a 'no go' area for any buildings or objects. This will prevent any unwanted objects from springing up and wrecking our day. We can do the same thing with a forest exclusion box, which prevents any trees or vegetation from appearing in the selected area. If you need to also exclude roads, rail networks or power lines from the area, then you simply use the Roads, Railways & Powerlines' Exclusion option.

One feature sorely missing from the exclusion zones option, is the ability to create a custom exclusion shape (no node or rotation option) as you are limited to pretty much squares and rectangles. To create an exclusion in the shape of an 'L' would mean creating two rectangles, which if we had nodes, would be far simpler and versatile.

An easy way to think of exclusion zones is as forcefields; they keep out the...undesirables (Figure 2).

Very Star Wars!

Figure 2

When adding exclusion zones, make them a little larger than necessary. Remember the wise words of Confucius: 'It is better to have a slightly bald landscape, than trees growing out of buildings.' Er...yeah!

Remember, any exclusion zone created will have zero impact on any objects or forests you add yourself.

In our never ending quest for scenery perfection, a good practice to get into is to fire up X-Plane and check your new scenery. Whatever you do, don't wait until it's finished! Like any good artist, constant checking is vital. When checking, if something looks out of place or not quite right, ask yourself 'Would this happen in real life?' If the answer is no, then it's back to the drawing board you go.

Figure 3 below, shows a magnified view of our runway. As you can see, there are roads leading directly towards it. Now, I don't know about you, but I'd be a tad bit concerned if I was coming into land and saw numerous vehicles approaching the runway (have I paid my car tax?). Apart from this, having vehicles this close to the runway looks unrealistic...especially when they suddenly just disappear!

Figure 3

As you can see in Figure 4, a Roads, Railways & Powerlines exclusion zone has been placed where we think the roads should end. This is great in that it cuts back on the roads but unfortunately it leaves lots of roads with dead ends. What we need to do here is to join them up so that they look more believable.

There are two ways in which we can do this. The first is to draw a tarmac polygon between the roads, but this has the disadvantage of being devoid of AI traffic. A far better solution to the problem would be to use Overlay Editor's Roads, Railways & Powerlines library (not to be confused with the Exclusion Library). Roads are string objects, which mean they can be lengthened and new nodes added. By doing this, our roads can now be joined together (Figure 4).

Figure 4

Now we have something approaching reality!

Well, there you have it...exclusion zones. I know we've spent a whole tutorial on them but I think it's a worthy topic. Remember, as mentioned at the beginning of this tutorial...every new custom scenery SHOULD contain at least one exclusion zone.

By utilizing this feature, you are, in effect, future proofing your scenery for whatever changes might occur to that particular area.

See you next time and have fun with scenery design.

Paul Mort
pmort76@gmail.com
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