TERRAIN_MIN_DEM_AREA

[leostr]

Hello everyone,
I've been playing around with a lot of the TERRAIN settings in the cfg file, and kind of starting to understand what each bit is doing - sort of  ;D
My question is, and I've scoured a lot of forums and not found the exact answer, but what is the DEM ? I am thinking it may have something to do with the Diameter of Mesh (guessing D & M); to quote the FS9 tips that have been posted here, for example "This is the highest value used to calculate the DEM radius " - just dont understand what the DEM radius is? Sorry if this is blindingly obvious, but can anyone offer some help with this?

[RIC_BARKER]

The "TERRAIN_MIN_DEM_AREA" value is the lowest value used to calculate the DEM radius based upon "TERRAIN_ERROR_FACTOR".

The "TERRAIN_ERROR_FACTOR" value must be between 0-100 and descibes an area, It is a linear scale.

"DEM" is just a term for the resoloution of the mesh being used, or the distance between the "points" that make up the mesh. This value is set in "TERRAIN_MAX_VERTEX_LEVEL" where the values are:

18 = 150m DEM
19 = 79m DEM
20 = 37m DEM
21 = 19m DEM

A 19m DEM is currently the highest supported I think.


The "TERRAIN_EXTENDED_LEVELS" entry is basically how many "virtual rings" are created around your aircraft, the boundary of the ring describing when and where the mesh switches from the "TERRAIN_MIN_DEM_AREA" value to the "TERRAIN_MAX_DEM_AREA" value.

By setting the "TERRAIN_MIN_DEM_AREA" to a low value (such as 10) and the "TERRAIN_MAX_DEM_AREA" to a high value (such as 100), and also setting the "TERRAIN_EXTENDED_LEVELS" value to a high number (I use 900, default is 1) you can imporve the performance of FS9 by allowing the mesh to get progressively more well defined as you approach it. It also looks better in my opinion.


I hope that helps,

Ric B.

[leostr]

Thanks, Ric - a very good expansion on whats already out there - i will have a play at lunchtime and see what happens  ;)

Leo

[JBaymore]

Ric,

Hi.  When I went in to my config file...... I found that the TERRAIN_EXTENDED_LEVELS value was set to a pretty weird 1307992 value.  I thought that was really a strange value in light of your posting above...so I changed it to your "900" to see what would happen.

Couldn't see any difference in fs2004 performance whatsoever.  Is there a specific RATIO necessary between the numbers?

The MIN_DEM_AREA was already set to 10 and the MAX_DEM_AREA was already set to 100.

Any thoughts on how it got to that really high number in there?  


I am still struggling with pretty poor framerates given my system specs.  So I Am trying pretty much everything I haen't already (which is all the basic stuff).

best,

...............john

[RIC_BARKER]

John,

What's "pretty poor framerates"?

Can you give a general descriton of how your FS is set up, and when/where the poor performance occurs?

Ric B.

[JBaymore]

Ric,

Thanks for the fast reply.

"Pretty poor framerates" means something like 10-15 on short final into international airports like KBOS of KJFK or on takeoff in the same kind of locations.  Which to me is unflyable.   Any urban/built up area drops my framerates dramatically.  

I don't care that I get OK rates up high and away from all the scenery.  For me the sim is a lot about takeoffs and landings with AI traffic around and the scenery  ;).  And of course the weather is a nice feature  ;).

This has been an ongoing exploration literally since the week ACOF came out....and has cost me quite a few bucks so far.  There is TONS of documentation of all the trials and tribulations I've had in various message threads on SimV.  I've had help from MANY kind people.... (including you I think)...... and nothing seems to work.  I've posted all that I have tried so many times here that I am getting sick of listing it  ;) .

About the only thing that I haven't done (and am pretty unwilling to do) now is a complete wipe of my whole system and reinstall everything from the blank hard drives up.  This is a machine that I use for more than flight simming....and such an effort would be VERY time consuming.

I cannot believe that this machine I bought just before ACOF came out (to run it) won't give me better results than I am getting...... GIVEN the reports that I see here that have many with far "lesser" systems saying that they are running the sliders "maxed" and getting FAR better framerates.  Either people are being "overly optimistic" or I am not getting the performance I should.

A while back I upgraded to an ATI 9600 pro to improve things.  Framerates got better but not too much over the 64 Meg card I was running before.  Then very recently ......in a fit of frustration....... I got an ATI 9800XT....... and got very little improvement over the 9600 pro as far as framerates went (visuals improved).  

All DxDiag reports come back fine, and so on and so on, ad nauseum.  Hardware accel is ON and functioning.  All latest mobo chipset drivers, sound drivers, and all that kinda' crap installed.

Anyway... I was mainly interested in any info you had on the function of the "Terrain_XXXXXXXX" code in the cfg file and how it works.

And again.... any idea HOW that number got so high in the first place?

best,

...............john

[RIC_BARKER]

John,

Not sure how that number got that high.

As regards your request for more info, I don't really know what you mean. Is there something specific you wanted to ask, or did you just want a general run-down of what it all means?

Ric.

[leostr]

Ric et al,

Sorry i've not given feedback to my on question - very rude  :-[ Well, made the changes. It seems that, while there is an improvement in texture sharpness, my dreaded blurries have made a comeback. Not sure how tightly integrated all these cfg settings really are, but i think that there's very much a case of change one setting, the others need to be changed to compensate. Its interesting, frustrating and timeconsuming, but i am determined to get the best possible experience that my hardware will permit. I must say though, but i am surprised that we are now pretty bedded down with this fab software, we know the nuances of a stable and on the whole impressive product, that it sometimes mystifies me taht there are still such a large number of questions about these [terrain] settings, we AFAIK, have not been given the breakdown offcially as to how these work from M$ !!
Thanks again Ric, i am gonna keep going on this one, and prob post screenies as "a pic can paint a 1000 words"...

[_526th_Fireman]

Hello pilots,

Well, I too have been "tinkering" with my [Display] settings in the .cfg file. Followed the tweak quide which was posted here at SimV awhile back. Got to noticing some blocks of textures that I didn't think should be there. Then........ after adjusting the setting to 900 in
"TERRAIN_EXTENDED_LEVELS" as per Ric's suggestion, the scenery looks better than ever. Don't ask me how but mine was a rediculous number like yours JBaymore, 12xxxxx or something. And I don't ever remember changing it. For fun, here are my settings in the [Display] section.

UPPER_FRAMERATE_LIMIT=0
TEXTURE_BANDWIDTH_MULT=100
[TERRAIN]
TERRAIN_ERROR_FACTOR=90.000000
TERRAIN_MIN_DEM_AREA=10.000000
TERRAIN_MAX_DEM_AREA=96.000000
TERRAIN_MAX_VERTEX_LEVEL=19
TERRAIN_TEXTURE_SIZE_EXP=8
TERRAIN_AUTOGEN_DENSITY=2
TERRAIN_USE_GRADIENT_MAP=1
TERRAIN_EXTENDED_TEXTURES=1
TERRAIN_DEFAULT_RADIUS=9.800000

[JBaymore]

Fireman,

I know that I never manually changed that value to the high number.  So there must be wither something that I installed that did it.... or the sim itself changed it somehow.  

The real question is WHY so high?  And exactly what function does that value take and how does it relate to the OTHER code lines?

best,

..............john