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Should Mesh complexity setting cause problems with terrain

jgarnold

jgarnold

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australia
I have just spent days trying to determine why I see terrain jutting into a lake I created for my airport. No matter what I did (using ADE) I was experiencing problems with small areas of terrain (land texture) jutting into my lake which was of a different texture from the terrain (land texture) on the 'land side' of the lake.
I created two threads in other forums (airport design) and received replies none of which fixed the problem I was experiencing.
In a last ditched effort I tried changing the Mesh Complexity and Mesh Resolution settings for scenery.
I had them set to 75 and 38m respectively.
When I 'reduced' them to 40 and 76m respectively my problem almost disappeared BUT when I set them both fully to the right my problem disappeared.

Could someone tell me is this normal? That these settings can cause problems with how coastlines can be displayed? Also what are normal settings and (apart from fixing my scenery problem) how else can they affect scenery.

Thanks
 
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Hi John:

IMHO, when creating / modifying scenery, it is best to always set the FS terrain complexity to 100 %.


When FS' Menu GUI slider setting for terrain mesh resolution is changed to 10 Meters or higher (smaller numbers of Meters for intervals between terrain vertices in the Quad Mesh grid on the ground), one also enables display of higher LODs and/or MIPMAPs for textures mapped to CVX vector terrain objects; thus one is effectively enabling display of higher "resolution" or detail in terrain textures mapped onto those 'ground' objects.


Setting FS' terrain mesh resolution slider to "full right" forces a 1 Meter interval between terrain vertices in the Quad Mesh grid on the ground.


When one sets a higher terrain mesh resolution, the FS terrain rendering sub-system will create a more detailed Quad Mesh grid which enables smaller intervals between terrain vertices, to which vector poly-lines and polygons are then able to be mapped with greater precision.

The resulting more detailed Quad Mesh grid having smaller intervals between terrain vertices will be present regardless of whether the underlying terrain mesh file supplies elevation data for points at Geographic coordinates that 'match' the intervals between terrain vertices on ground which are enabled by the Quad Mesh grid itself.

However, the Quad Mesh grid terrain vertices will also be assigned an elevation by interpolation of the nearby elevation data points sourced from within the terrain mesh BGL currently having highest "effective" display priority within the local FS terrain engine rendering of the ground.


BTW: FSX default scenery provides a terrain mesh BGL with a LOD-10 (38.2 Meters between elevation data points on ground) resolution for your project area:

FS default "local" terrain mesh file for your project area is:

[FSX SDK install path]\Scenery\0101\scenery\dem0101.bgl


...as cited in my reply to another thread related to your current project here:

http://www.fsdeveloper.com/forum/th...rial-on-creating-airports.438455/#post-756081


And IIRC, FTX PNW region pack provides a LOD 4-12 (minimum 9.6 Meters between elevation data points on ground for the USA portion) and LOD 4-11 (minimum 19.1 Meters between elevation data points on ground for the Canada portion ) resolution terrain mesh ...when installed and set active.



Since AFAIK Canada does not have (free) publicly available elevation data beyond 23 Meters resolution, this free data 'may' be compiled for FS at 19.1 Meters between elevation data points on ground (aka "LOD-11" resolution) ...if you have such a 3rd party terrain mesh installed / set active.


NOTE: There are indeed some FS terrain CVX vector scenery content rendering anomalies involving higher resolution slider settings that have been reported:

http://www.simforums.com/forums/scenery-texture-resolution-setting_topic46516.html

http://www.simforums.com/forums/solved-runway-failure_topic46481_post281657.html#281657


NOTE: If by any chance you still have residual custom scenery files (ex: terrain mesh with LODs 4-12 resolution, and/or CVX vector objects with assigned elevations) from 3rd party sources being processed by FS due to having previously had any version of FTX PNW region or FTX Global, and/or FTX Vector or other add-on 'vector' and/or 'terrain mesh' scenery packages installed, those may require additional and more complex considerations to make your own custom scenery package display properly. :alert:

Thus it would be difficult to identify exactly what may have enabled "small areas of terrain (land texture) jutting into my lake which was of a different texture from the terrain (land texture) on the 'land side' of the lake ...as you reported above, without knowing more about what scenery BGL files you have installed and set active in the FS Scenery.Cfg file via Area entries in the FS scenery library GUI stack of layers.

Additionally, it would be difficult to identify exactly what "effective" display priority your custom CVX vector scenery content may have in FS at run time without knowing more about what scenery BGL files you have installed and set active in the FS Scenery.Cfg file via Area entries in the FS scenery library GUI stack of layers.


The effective 'placement' precision for your custom CVX vector scenery content may vary according to how close together the vertices are for poly-lines / polygons, and the overall Geographic extents of your BGL file may determine the effective display priority ...in FS at run time.

Furthermore, one must know whether or not specific portions of your custom CVX vector scenery content was created as (2) separate objects relative to QMID-11 quad "clip" boundaries, so that there will be (1) segment of any larger objects that 'cross' such quad extent boundaries placed within each of the (2) adjacent QMID-11 quads in the vicinity of your Sechelt Water Aerodrome scenery project location ...as this may determine effective display priority, and perhaps whether your custom CVX vector scenery content will even be possible until segmented properly for 'quad clipping'. :pushpin:


FYI: There may be a way to 'force' your custom CVX vector scenery content to have a higher "effective" display priority in FS at run time, by adding several tiny 3-sided polygons with assigned locally-compatible elevations at each vertex in (4) locations surrounding your project area at LOD-4 quad span distances, which will effectively give your CVX vector scenery the ability to display regardless of whether you or any other intended end users may have custom scenery files (ex: terrain mesh with LODs 4-12 resolution, and/or CVX vector objects with assigned elevations) from 3rd party sources installed. :idea:

The purpose for these remote polygons is to trigger loading of your custom CVX vector scenery BGL and to force modification of scenery data from other CVX vector and/or terrain mesh BGLs when flights are launched from locations outside distances the equivalent of LOD-4 quad extents ...prior to then flying into your local scenery project area. ;)


This might best be done in SBuilderX with a LOD-4 terrain grid turned on in the background for the project used to create your custom CVX vector land / water and shoreline scenery content; you may wish to review the concepts for this type of method discussed in these threads:

http://www.fsdeveloper.com/forum/threads/flattens-inactive-under-specific-circumstances.438192/

http://www.sim-outhouse.com/sohforums/showthread.php?102585-Heron-s-Nest-Elevation-Problem


[EDITED]

Segmenting CVX vector scenery content into (2) separate objects relative to QMID-11 quad "clip" boundaries, so that there will be (1) segment of any larger objects that 'cross' such quad extent boundaries placed within each of the (2) adjacent QMID-11 quads in the vicinity of your Sechelt Water Aerodrome scenery project location ...might best be done in SBuilderX with a QMID-11 terrain grid turned on in the background for the project used to create your custom CVX vector land / water and shoreline scenery content.

[END_EDIT]


PS: A table summarizing terrain grid Quad / Area Point extents and LODs etc. ...is here:

http://www.fsdeveloper.com/forum/threads/flattens.425495/page-2#post-633002



Hope this info helps with fine-tuning display of your scenery with default or custom terrain mesh and CVX vector scenery object BGLs. :)

GaryGB
 
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Thanks Gary

Scenery is really a complex matter.
LOD is starting to "come back to me" now that you explain how they affect scenery. If I remember correctly when I had to use SBuilderX to create scenery for islands I wanted I needed to understand LODs.
 
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