mesh2kml

Export textured geometry (surface or patch) to GoogleEarth as a KML and a Collada DAE files

Export textured geometry (surface or patch) to GoogleEarth as a KML and a

Collada DAE files

mesh2kml(...) -surface or patch inputs, see bellow

mesh2kml(...out) -one common output filename or paths to {dae img kml}

mesh2kml(...out,prp) -Collada & GoogleEarth property value pairs

color: color, default=[0.7 0.7 0.7] OR..

image, RGB(A)|BW(A)|filename (optional)

alpha: opacity, default=[1] (opaque) OR..

image, BW|filename (optional)

latlon: flag to interpret xyz as Lat,Lon,Alt, default=0

twosided: flag to render faces from both sides, default=1

position: [latitude_deg longitude_deg altitude_m]

altmode: default='absolute', 'clampToGround', 'relativeToGround',

'relativeToSeaFloor', 'clampToSeaFloor'

orientation:[heading_NtoE pitch_NtoUp roll_UPtoE] (deg), default=[0,0,0]

scale: [x y z] scale factors, default=[1,1,1]

camera: [heading_deg tilt_deg range_m]

M = mesh2kml(...) -return final properties as struct

Surface:

mesh2kml(x,y,z...) -NxM vertex coordinates

mesh2kml(x,y,z,c...) -NxMx3 face colors, last row & col ignored (TO DO)

mesh2kml(x,y,z,u,v...) -NxM texture coordinates

mesh2kml(..,nx,ny,nz...) -NxM vertex normals

mesh2kml(S) -above surface properties as struct

Patch:

mesh2kml(P...) -patch properties as struct, with fields:

vertices: Nx3 vertex positions

faces: Mx3 triangle faces (right hand rule)

normals: Nx3 vertex normals (optional)

uv: Nx2 texture coordinates for each vertex

Remarks:

-Collada (dae) files can be dragged and dropped into GoogleEarth.

-A kml file is written only if 'position' is provided.

-For lat,lon 6dp gives ~15 cm precision at equator, 8dp is ~1.5 mm.

-Textures wrap circularly if UV is outside the [0-1] range.

-Texture pixels blend and image edge pixels blend with opposite edge.

-If normals are not provided they are auto generated. Vertices shared by

triangles get a smoothed normal using triangle area weighting.

-To avoid normal smoothing when specifying a patch each vertex should be

referenced by only one face.

-Faces are auto generated using vertices(:,1:2), if missing.

Notes:

-Altitude exaggeration in GoogleEarth will affect the model's origin.

-The only way to visualise textured polygons in MatLab is to draw each

polygon as a quad with its own image chip, which is very limiting.

-To generate dae template draw a polygon in Google SketchUp 2017 > export

as kmz > open kmz with winzip > extract dae file > modify as needed.

-SketchUp duplicates all polygons to face both ways, but mesh2kml uses an

undocumented Collada tag: <effect><extra><technique><double_sided>.

-SketchUp can export a quad mesh dae but they don't work in GoogleEarth.

-GoogleEarth ignores camera references in dae file.

To do:

-Allow one colour per face, see surf2patch.

-Allow multi patch input using array of structures as input.

-Allow quad patch input by converting it to a tri patch.

-Allow input to be a handle to a displayed surface or patch object.

-Allow export as kmz file.

-Use ridge detection when triangulating surfaces.

-Test generated normals.

-Add more patch examples.

-Remove thin triangles from patch inputs.