I thought I knew what these were, but I think I have confused some of them. Could someone kindly confirm what each of these file types typically do, according to custom naming:*VTPL.bgl*VTPP.bgl*VTPX.bgl*LWM2.bgl (This one LandWaterMask I assume)Thanks,Martin

I thought I knew what these were, but I think I have confused some of them. Could someone kindly confirm what each of these file types typically do, according to custom naming:*VTPL.bgl*VTPP.bgl*VTPX.bgl*LWM2.bgl (This one LandWaterMask I assume)Thanks,Martin

Hi Martin:Just as a quick reply: :( "VTP" means FS8 or FS9 Vector based Textured Polygon objects, usually with a Type 1 or Type 2 designator."LWM" means Land/Water Mask polygon object (designated with a Type 2 or Type 3 designator when it is one of the 'special' types) as described in the FS2004 Terrain SDK "Terrain Vector Data.doc":"The LWM Polygon: LWMPoly2 and LWMPoly2ExPolygons exist in the data stream following the LWMDataAreaDrawPolygons structures. The LWMPoly2 structure defines the fill type (land/water) and the number of points in the polygon. There are two structures to use depending upon the number of points in your polygon:Use LWMPoly2 for polygons with up to 62 points. Use LWMPoly2Ex for polygons with 63 to 191 points. The system cannot handle polygons with more than 191 points. Break these up into smaller polygons.""The Sloped LWM Polygon: LWMPoly3 and LWMPoly3ExThe LWMPoly3 structure adds the ability to include height information for each point in the polygon and is normally used for wide river channels that gradually slope downhill. There are two structures to use depending upon the number of points in your polygon:Use LWMPoly3 for polygons with up to 62 points. Use LWMPoly3Ex for polygons with 63 to 191 points. The system cannot handle polygons with more than 191 points. Break these up into smaller polygons."Proposed Interpretation (pending one's own detailed review of above FS2Kx SDK docs)...and Ground2k docs in "Ground2K4 V5.1" by Christan Fumeyhttp://library.avsim.net/esearch.php?CatID=fs2004util&DLID=39207...and "Ground2K for Beginners" Luis Feliz-Tirado):http://library.avsim.net/esearch.php?CatID=fs2002sd&DLID=33724*VTPL.bgl = VTP Line(s) ?*VTPP.bgl = VTP Polygon(s) ?*VTPX.bgl = VTP Exclude(s) ? <usually specific to a layer number>*LWM2.bgl = LWM type 2 Polygon(s) ?PS: You may wish to decompile the BGLs to *.asm (*.BGS) files with Jim Keir's "LWMViewer" version 1.x:http://www.jimkeir.co.uk/FlightSim/LWMViewer.html...and/or to *.SCA files with Winfried Orthmann's "BGLAnalyze version 3.1":http://library.avsim.net/esearch.php?CatID=fs2002sd&DLID=27375...to determine their intended function. :( Hope this helps ! :( GaryGB

Thank you very much!M. :(