I'm exploring ways of converting 3D GIS data from ArcGIS to kml/kmz format for GoogleEarth and I keep running into all kinds of troubles. From what I understand there are three ways of exporting to kml: 1. Multipatch to collada - it creates a collada file as well as a kml with the spatial reference of the model. There are three problems here. The first is the shader/material that gets created for every part of the exported model. It is simply shadeless which does not look good at all. You can see it on the first model on the first attached image. The second problem is that the multipatch is split into a few separate models (eg. floor, roof, walls.. the more complex the model the more parts get created). It duplicates vertices and gives them normals with directions different than it would be on a single-part model (it may be, I don't know if it is in fact, a problem, cause some problems with lightning). I can open the collada model in some kind of 3rd party 3D graphics editor then remove the materials (or change them to shaded ones) and join all the geometries into one model. But why isn't it done during the export process? The last but not least problem is that collada models georeferenced by the kml file created by Multipatch to collada tool have... offseted rotation. You can see it on the second attached image (compared to the same multipatch exported with Layer To KML). 2. Layer To KML - it gives me some strange flickering triangles here and there and some of the triangles that were present on the multipatch it was created from are missing. I tried doing it with models of different origins (different companies providing models of 3D cities, simple extruded polygons and it's still a problem). It also creates a Multi Geometry kml from which only the first element can be edited in GoogleEarth so you can't do the cleaning up in it. 3. The ArcGlobe - ArcMap Map to KML way (described here. I can't provide an image, because the kmls generated that way keep crashing my GoogleEarth...
Am I doing it all wrong?
[ATTACH=CONFIG]17246[/ATTACH] Fig. 1 Starting from the left: model obtained by Multipatch to collada, model obtained with Layer To KML, 2D vector layer extruded inside Google Earth.
[ATTACH=CONFIG]17247[/ATTACH] Fig. 2 Comparison of two models - the darker one was exported with Layer To KML, and the lighter with Multipatch to collada. Notice that the models are not aligned (rotation) correctly.
