NZFF

"...changing "TERRAIN_AUTOGEN_DENSITY=5" to a greater number" may or may not keep producing an increase of autogen tree density if one uses settings higher than 30 ...I've personally not tested beyond 30.

This is of course changing something in the FS autogen display engine, and there probably is a maximum of trees that the rendering engine can handle before performance begins to become over burdened in any version of FS.

BTW: Holger Sandmann recently discovered that the previous FS Developer Community "word-of-mouth" assumptions regarding FS limits to "displayed Trees or Buildings" directly correlating with autogen annotations in the SDK specifications of (IIRC) 600 annotation footprints per LOD 13 tile in FS9 and (IIRC) 10 times that in FSX ...were INCORRECT.

This is substantiated by a statement in the FSX (ESP) SDK: "There is no limit to the number of footprints", and IMHO this allows one to infer that the number of trees displayed per LOD tile may be controlled by the number of annotation footprints per tile.

http://msdn.microsoft.com/en-us/library/cc526979.aspx

But this statement does not further explain that the number of footprints displayed in FSX is controlled by the FSX.Cfg tweaks parameter "TERRAIN_MAX_AUTOGEN_TREES_PER_CELL=", and it is easy to forget that the earlier FS version SDK docs explained that LODs are "areas" or "quads in a quad tree matrix", and that in a LOD 13 quad there are 256x256 "area points" or "cells" which make up each LOD 13 area / quad or "tile".

In his latter work on the FSAddon Tongass Fiords scenery product, Holger determined that the parameters which some have used (ex: in FSX.Cfg file) for attenuating displayed density of autogen trees and buildings resulting from a given autogen density slider setting in the FSX GUI may work differently than previously assumed via changes to:

[TERRAIN]
TERRAIN_MAX_AUTOGEN_TREES_PER_CELL=2000 // (or less; FSX default if not specified=4500; Max=6000
TERRAIN_MAX_AUTOGEN_BUILDINGS_PER_CELL=1700 // (or less; FSX default if not specified=3000; Max=6000

http://support.microsoft.com/kb/555739

NOTE: Nick Needham (Nick_N) has questioned the appropriateness of implementing high density autogen annotation in combination with autogen attenuation tweaks:

http://www.simforums.com/forums/forum_post...&PID=198224

Nick's post refers to an in-depth (and briefly rather heated) discussion on this at AVSIM recently:

http://forums1.avsim.net/index.php?showtopic=279576

Holger's discovery suggests that "TERRAIN_MAX_AUTOGEN_TREES_PER_CELL" does not refer to a limit of trees displayed per LOD 13 tile or "cell".

IIUC, it instead refers to the number of autogen annotation rectangles or annotation rectangles/polygons allowed to be displayed per LOD 13 tile or "cell" ...a limit on display of trees apparently was only indirect on the basis that each LOD 13 tile has a max limit of displayable footprint rectangles of 600 in FS9, 5000 in FSX.

There may be ways to change the types of trees displayed in the default FS autogen for FS9 and FSX, but I don't recall if for FS9 this is defined anywhere other than the default AGN files in the [FS install path]\Scenery\World\Texture folder.

However, in FSX, once can additionally change the autogen tree definitions used by decompiling, editing and re-compiling the autogendescriptions.spb files, although this is not really necessary (or desirable) to do, even though it was done in the early days of struggling with FSX performance before the SP1 and SP2 improvement were released.

The take away from this if you wish to experiment:

Bump up your autogen in the FS9.Cfg file settings "... by changing 'TERRAIN_AUTOGEN_DENSITY=5' to a greater number" and see how far you can go before problems arise.

In FSX.Cfg one would presumably hit a limit based on performance eventually, but the density of tree annotations out of the box is already (IIRC) 10 times greater than the annotation footprint density in FS9, so YMMV.

FYI: This entire discussion is regarding behavior of default FS scenery as a function of the land class instructions).

When dealing with custom photoreal scenery for which substitute autogen annotation files must be created / used, I believe one can exercise additional control to achieve a greater tree density up to a limit of 600 autogen object footprints per LOD 13 tile in FS9 and up 6000 autogen object footprints per LOD 13 tile in FSX.

In FSX, because many legacy sceneries are allowed to be loaded and displayed (even some files from FS2000), the FSX rendering engine will load not only an FSX SDK format AGN annotation file (which has a slightly different name), but also any AGN annotation file from FS9 (and I would assume from FS8 and FS7 too) if they were active for the area of one's flight and the AGN files were in the local paired twin \Texture folder next to the \Scenery folder.

This could be a good or bad thing depending on the impact of the FS rendering engine's ability to keep up.

It may also be that in pre-FSX versions of the sim, we can again purposely use multiple AGN files "if" the FS file naming is different for the AGN files from the other versions of the AGN files (I haven't looked into whether this is the case for pre-FS9 AGN file names).

The ability to display more autogen trees with one's autogen slider density max right in either version of FS is likely attenuated by 2 things:

1.) FS9 'TERRAIN_AUTOGEN_DENSITY=x' ("x" set via experimentation; varies by system performance, but indirect limit via number of AGN footprints per LOD 13 tile / "cell" max=600)

2.) FSX 'TERRAIN_MAX_AUTOGEN_TREES_PER_CELL=x' ("x" set via experimentation; varies by system performance, but indirect limit via number of AGN footprints per LOD 13 tile / "cell" max=6000)

Some additional considerations:

http://205.252.250.26/cgi-bin/yabb2/YaBB.pl?num=1234752227

http://www.newsite.fsdeveloper.com/forum/s...ead.php?p=95608

http://www.fsdeveloper.com/forum/showthread.php?t=18250

Oh, and there are probably other un-published tweaks that ACES knows about that we never heard of because they wanted to prevent people from "bringing FS to its knees" (and then blaming them for a flight sim that could not deliver) ...like this one that Torgo wrote about one time in a moment of frivolity:

http://blogs.technet.com/torgo3000/archive.../31/413418.aspx[/quote]

Next logical step is to take this to either the AvSim Scenery Discussion Forum or the FSDevelopment Forum and see what others have to say.