FS2004 scaling mesh source files to avoid the interpolation of the resampler

[simulondo]

Hi

I've come back to FS9 for fun and I'm trying to improve the resolution of some mesh creating them from zero. But I want to avoid the interpolation which the resample does to adjust source files to the LOD assigned. I would prefer scaling them previously using gdal which have a better interpolation modes (cubic).

As the photo scenery is linked to cells LOD 13 (256px X 256px) I suppose the mesh will be linked to the LOD that we assign in the .ini. In my case I want to generate the scenery with a resolution 19m (LOD 11). My question is: Would it be correct to say the size of the cells for LOD 11 have a resolution of 768x768?

The reason of my question is: if I would know how many cells my mesh fills, and the size, in px, of those cells, then I would obtain the final size of the source image. In this way I can avoid resampler scale them (I don't know if it would be more correct to use 'sampling' instead of 'scale' in this case).

Regards

 

[GaryGB]

Hello Jose:

This should be an interesting project.

There is still some info to be found online regarding legacy SDK- and custom- methods for photo-real ground texture tiles made (in part ?) via SDK Resample.

Here's some initial info (I'll post more on the specific concept of slicing tile images 'resampled' via either the old (pre-FS2004 ?) SDK Resample and SDK ImageTool, or via a non-SDK graphics application ...as time permits later today):

https://www.fsdeveloper.com/forum/threads/mesh-lod.438258/

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=2ahUKEwjl3KbI6IbhAhUQZawKHZDMDt8QFjAFegQIAhAB&url=https://www.avsim.com/forums/topic/76324-old-resample-inf-for-custom/&usg=AOvVaw1IOPYLIYJ4-i0HTI6SSWmd

https://webcache.googleusercontent....ple-inf-for-custom/+&cd=6&hl=en&ct=clnk&gl=us

https://www.fsdeveloper.com/forum/threads/geotiff-blending.431787/

https://www.fsdeveloper.com/forum/t...g-split-to-different-heights-with-mcx.427856/

https://www.fsdeveloper.com/forum/threads/flattens.425495/post-633002

[EDITED]

Some additional links:

https://www.google.com/search?q=AVS...WotYnhAhVsmK0KHRg1DOYQ8tMDCHA&biw=964&bih=674

[END_EDIT]


AFAIK, SDK Resample makes 257x257 tiles and overlaps them at East and South borders within the FS quad mesh terrain grid, as a type of custom Land Class.


PS: Other methods to be considered is the high resolution VTP tiles method (compiled via BGLC ?) by Luis Sa' in SBuilder for FS9 (aka "SB205"), and the flat 3D non-MDL photo-mesh ("TexPoly" compiled via SCASM ?) which IIRC was used by Gottfried Razek in some of his pre-FSX "BlueSky" photo-reaL sceneries.

GaryGB

 

[simulondo]

As usual Gary, very informative, I appreciate. I had read previously a couple of those links but not most of them. I've seen very interesting points in the first one. I have to read it carefully.

Back to my initial question, my doubt is related to the mesh generation more than photoscenery. Thankfully, after spending some time testing and reading several old posts of Rhumbaflappy at AVsim about photosceneries in FS9, I've achived promising advances. But when I've started to work with the mesh I'm not sure about the size of the cells, as I said in the first post.

But right now, I'm going to read some of those posts. Thank you.

Regards

 

[GaryGB]

https://www.fsdeveloper.com/forum/t...rpolation-of-the-resampler.445003/post-818737

As the photo scenery is linked to cells LOD 13 (256px X 256px) I suppose the mesh will be linked to the LOD that we assign in the .ini. In my case I want to generate the scenery with a resolution 19m (LOD 11). My question is: Would it be correct to say the size of the cells for LOD 11 have a resolution of 768x768?

With regard to this specific question, you might wish to review this thread first, for a table of info that may answer that:

https://www.fsdeveloper.com/forum/threads/flattens.425495/post-633002

[EDITED]

Imagery is Pixels/Meter and mesh is Elevation points/Meter for illustrative purposes in the table linked above.

Both are Raster pixels mapped to terrain quad grid vertices; however, actual mapping of Pixels to the FS quad terrain grid is calculated and mapped to grid vertex points by SDK Resample using 'fractional degrees' on the X and Y axes.

https://www.fsdeveloper.com/forum/threads/photomesh-4-75m-pix-not-4-8m-pix.886/


AFAIK, Raster pixels mapped to terrain quad grid vertices are re-sized to 'fit' target quad location in FS' 3D world model.

https://www.fsdeveloper.com/forum/threads/qmid-question.438142/post-752644

IIUC, each WGS84 source Pixel will be subject to an individually calculated X-Y size for its destination quad within each LOD.

NOTE: Earth actually is an Oblate Spheroid ...thus the use of WGS84 GIS cartographic format for SDK Resample source data

https://en.wikipedia.org/wiki/Spheroid

https://en.wikipedia.org/wiki/World_Geodetic_System



I am not sure one achieves accurate FS Pixel calculations via non-SDK Resample / non-GIS methods of X-Y interpolation.

Thus, use of a non-GIS graphics application to "resample" Pixel sizes via ex: 'cubic' interpolation may-, or may not- ...be accurate for FS' 3D world model in versions of FSX and P3D.

But, IIRC, the world terrain model in versions of FS prior to FSX / P3D was rendered in a somewhat different manner.

https://www.avsim.com/forums/topic/...n-bad-textures/?do=findComment&comment=556150

https://www.avsim.com/forums/topic/81273-observation-about-fs-using-wgs84-geolatlon-bad-textures/

https://www.avsim.com/forums/topic/77854-lod11-span-in-metres-urgent/?do=findComment&comment=538940

https://www.avsim.com/forums/topic/77276-a-question-for-everyone/


One may test for accurate FS2004 Pixel calculations via non-SDK Resample / non-GIS methods of X-Y interpolation when:

* Source data has a local GIS cartographic projection as non-warped tiles of equilateral dimensions (ex: UTM etc.)

...before it is re-projected to (EPSG:4326) aka Geographic (Lat-Lon) projection / WGS84 datum for use with SDK Resample.

[EDITED]

GaryGB