Ahoj,
Marek asked me to write some words here in english for Kendzi about my experience with 3D.
I have written a short tutorial for verry easy buildings you can see it here: (in german only but I think the pictures tell much about the content)
http://wiki.openstreetmap.org/wiki/User:Viw/OSM3D
I had prepared a hole part of the city and renderd with osm2world, to show other persons what they can expect from osm3d today:
http://wiki.openstreetmap.org/wiki/File:OSM3Dworshop_Prohlis_3D.png
But if I try some more detailed places I found my own barriers:
http://vkw.bplaced.net/osm/Pirnaischer_Platz.png
http://vkw.bplaced.net/osm/Pirnaischer_Platz.osm
The first problem for beginners is, that the different languages from rooftable are different. Only the site in polish has the correct types for roofs. The english and german one has “_” instead of “.” for different subtypes.
The pictures are not the same so you can not be shure witch parameter is in use for witch thing in reality. In all pictures I miss the startpoint withc ist verry important for Types like 2.2
There could be another problem about tagging. I have written E-Mails with User:Tordanik about implementation 3dr in osm2world. Because it seems to me it look better then the lines only in Kendzi3D. But he don’t want only nubers as tags. Because it is not really human readable. Maybe you and he can find a solution for this.
The next problems for me was that it seems to me that some parameters are ignored so the roofs don´t look like I expecet. A nother problem in the exampel was the smal building beetween the building at the edge and tho long one. Although I use type 2.0 the roof is not conected to the wall at the right site.
An other problem is the startpoint. Some buildings I had to draw three times. Maybe we can use a tag for startpoint. I proposed 3dr=start or 3dr:start=yes. Marek has told me about 3dr:direction=begin. Maybe we need different starting points later we can use 3dr:roof=start or 3dr=roofstart like Marek proposed in german forum as answer abput my questions.
The biggest problem I think is the data witch is produced. Because if you look of our exampel you find buildings in buildings witch not look very well in mapnik rendering. So maybe we should sepperate ground view from 3dr tagging.
User Suncobalt has told that he think building:roof:shape=3dr isn’t nessary if you use 3dr:type=
I think he is right and it is better if you can render the roof with only 3dr:type without the need of building=yes. Tordanik propesed building:part=yes for parts of buildings in the ground view witch are higher than others.
I hope my english is not to bad.