to populate the terrain with buildings as easily as possible, it may
make sense to leverage models and tools from the world of CAD software
unfortunately, even today, the vast majority of CAD is only 2D
blueprints, not 3D models
conversion of 2D CAD to 3D is generally a difficult, ambiguous process
requiring experienced users and lots of effort
there are no free software tools for 3D architectural CAD - if you know
of some, please tell us
CAD File Formats
The most common formats are those that originated with AutoCAD: DXF
and DWG
DXF is a very inefficient ASCII format, generally well known and
well supported, meant for exchanging files between CAD users
Dime is a C++ library
for reading and writing DXF file data, with a strange "dual" license,
GPL for use in Free software and a commercial license for commercial
use.
dxflib is
another DXF library, also with a dual GPL/commercial license
dxf2gl is a
small, old code which loads only 3DFACE entities from DXF files
complete CAD package, $4300, optional raytracing and site layout at
$600 each
their technology hype is
'The Virtual Building', claiming that you can create one 3D model
for all uses, including visualization and producing 2D construction
blueprints
99.6.8 received 4 sample models, in 3DS format, tried viewing them
in 3DS MAX, the models look decent
$2500 + $900 "subscription", so $3400 total, with discounts for
existing AutoCAD users
like ArchiCAD, a building modeler with high-level parametric
representation for walls, windows etc.
the company was bought by Autodesk, so price seems to depend on your
local Autodesk dealer
appears to be very powerful, with not only parametric architectural
components, but also topographical terrain editing features (like WCS
Terraffectors)
a highly parametric and reasonably priced CAD tool; tested some 3DS
sample output and found some issues including lack of smooth shading on
curved surfaces, mysterious units, and coplanar Z problems when loaded
into OSG
cons: very limited palette of materials - for example, no
sheetrock or gravel, does floor plans only - no structural composition of walls
or roofs, but doesn't draw the actual materials, no 3D export,
unstable.
Newer version 4.0 now has OpenGL rendering - Ordered a copy to
evaluate it.
other low-end consumer titles, which appear to be quite similar to the
above package:
Floorplan® Plus 3D Deluxe v4.0
Sierra ® Complete Home® v2.0
Planix® Home Designer Deluxe 3D v3.10a
Historical
AutoCAD Plugins
EasySite
$300 from Cad Easy Corp.,
runs only inside AutoCAD
semi-automatically creates roads, cul-de-sacs, landscapes,
sidewalks, curbs, and houses
still somewhat manual modeling, but allows for very
sophisticated intersections and parking lots
Cad Easy also now sold a version of the classic old program Facade, which turns AutoCAD floor outlines rapidly into 3D
building models