To be precise higher sceneries overwrite only when they provide changed data.

In case a higher scenery does not contain data of the same type (or for the same area) lower sceneries will not be overwritten.

I put a strong emphasis on this because people often ask me whether their mesh should be over FTX Global sceneries.

It does no matter FTX Global does not contain any mesh data so their position in relation to each other is insignificant.

But there are some guidelines that you should follow especially when you are not fully aware what data a scenery contains.

The same applies (but usually is not necessary its just a precaution) to points of interest, landmarks, etc.

In case you are not sure whether your area sceneries contain mesh place your global mesh below other area sceneries.

Top layer of ORBX sceneries contains two entries and AA group.

In case of FTX Vector do not use it with other vector sceneries or be very careful with them working together (test them).

The order depends on your choice (which scenery should overwrite the other in case of conflict).

I do not recommend using two landclass sceneries for the same place in the same time.

In my example the order does not matter as my Scenery Tech Africa is covering a different part of the world than ORBX openLC Europe and N.

Orbx Global Fsx Download