https://www.fsdeveloper.com/forum/t...pears-as-i-get-close-to-it.443095/post-802036
I am thinking that it is a size issue. I am thinking that I need to do it in sections. But how would one map several area's together like a quilt? Or does the SBuilderX automatically do this via tiles systems when compiling? Is there a limit?
I looked up LOD's in the SBuilderX and nothing is listed via the search in the help manual.
I would be grateful for any input on this.
Bill
LHC
Hi Bill:
Generally speaking, if one wishes to create terrain mesh and/or aerial imagery at high resolutions, one must limit the amount of source data in the working set being processed and output by SDK Resample to a BGL size of
no more than 2 GB.
FYI: One can create a
multi-source *.INF file that defines more than (1) data source file to be submitted to SDK Resample.
In such cases, areas of Geographic coverage for each source data file are individually specified by
*.INF parameter values.
Alternatively, if Geo-referenced TIFF (aka "GeoTIFF") source file formats are used, a simpler
*.INF file structure may be used, and SDK Resample will automatically read the Geographic data that it requires from the GeoTIFF file itself.
SDK Resample then processes the source data (
...and internally eliminates redundant source data if areas of coverage 'overlap').
https://msdn.microsoft.com/en-us/library/cc707102.aspx#TheResampleTool
BTW: There are some work-arounds up to allow perhaps up to a 40% larger than 2 GB amount of source data in the working set being processed, provided that final output by SDK Resample is a BGL with no more than 2 GB size (otherwise Resample will either reject the processing session with an error message, or will simply fail with no error message).
Those work-arounds involve use of TIFF (or preferably Geo-referenced TIFF aka "GeoTIFF") source file formats compressed with ('non-lossy') LZW compression; this results in up to a 3x size reduction of 'some' types of source data submitted to Resample.
During processing of LZW compressed source data, however, Resample must internally de-compress, process, then re-compress the data, so
compilation times typically may run between 2 to 4 times as long as data NOT LZW compressed.
The MS Game Studios - ACES' implementation of PTC ('lossy') compression by SDK Resample can also reduce output BGL file size formats independent of whether TIFF source files are compressed with ('non-lossy') LZW compression.
For example:
* A
*.INF parameter value of "
CompressionQuality = 85" reduces BGL size by ~40% ...with little loss of visual quality;
* A
*.INF parameter value of "
CompressionQuality = 100" reduces BGL size by ~0% ...with no perceptible loss of visual quality
Ultimately, if one intends to provide terrain mesh and/or aerial imagery BGLs that cover much larger areas, or if one wishes to provide such scenery at higher resolutions than can be processed in a single SDK Resample session and/or in a single (max. 2-GB) BGL, one may need to output
multiple BGLs from SDK Resample.
Adjacent Geographic coverage areas may be manually compiled as separate SDK Resample processing sessions.
Alternatively, a more complex multi-source
*.INF file can then be used to direct SDK Resample to output multiple BGLs, with one for each adjacent Geographic coverage area ...via 'batched' SDK Resample processing sessions.
On a practical basis, if one will
not be flying "
Low-and-Slow" over terrain mesh, only lower LODs will be seen at 'typical' in-flight altitudes. so lower resolution source data (
ex: 10 to 30 Meters / Pixel) may be used.
9.6 to 38.2 Meters / Pixel = LODs 12 to 10 for
terrain mesh
However, with
aerial imagery, one must 'force' output of
LOD-13 or higher in order to achieve display over default scenery.
Depending on how large an area one wishes to cover in ones scenery, this 'may' fit in a single BGL.
But if one
will be flying "
Low-and-Slow" over terrain mesh, higher LODs might be seen at those in-flight altitudes. so higher resolution source data (
ex: 30 CM to 5 Meters / Pixel) may be used.
30 CM to 5 Meters / Pixel = LODs 17 to 13 (~Zoom levels 17 to 13 for aerial imagery)
Depending on how large an area one wishes to cover in ones scenery, this 'may' likely require multiple BGLs.
Hope this helps explain a bit more, ones options for use of SDK Resample.
GaryGB
