Blender is another popular 3d modeling application, its files are in Blender format and have a '.blend' extension. The AC3D model files are in 'ac' format and have an '.ac' file extension. It is good that FlightGear uses a non-binary format for aircraft models. AC3D is the format FlightGear uses 'natively' for aircraft models. Two major 3d design applications are AC3D and Blender.
Those are two good reasons to get your model out from GMAX's trap. Moreover, it is desirable to store 3d models in a format that has some longevity and is human readable. The problem to solve is getting an aircraft model from GMAX's proprietary binary 3d format into a format more in keeping with the FlightGear community. It also can tell you which features some formats lack. This chart explains which formats PLIB recognizes and what features it supports. Not all features of certain formats are supported in a given version of the library. If you dig deep enough into PLIB documentation, you may find in a very obscure pageĬontaining a table of formats PLIB is capable of opening and saving. This utility is dependent on the PLIB library. As of this writing, _3dconvert_ can only open or save in formats supported by PLIB with any restrictions PLIB places on them. It depends on a library called PLIB for making conversions between formats. Exporting and importing 3d files for FlightGear can involve using the bundled '3dconvert', although it does not have to, given there are a number of third-party converters and import/export tools for 3d modeling applications. In FlightGear, a utility called '3dconvert' is bundled with the source (Windows binary available here), which has the ability to convert a number of 3d file formats. What happens if you export or import using a tool that does not support sub objects? You get a wing with all its parts 'welded' together so they cannot be individually manipulated. Some export or import tools may not support independent 'sub-objects' and will merge all the parts of a wing into single object (or 'mesh' as objects consisting of polygons are generally called in the 3d world). It is desirable to export the entire wing with all its parts intact and _independent_. There may be hardware such as stays, guidelines, actuators, etc. A wing may consist of the wing body, the aileron, the flap and perhaps a wingtip. When you create an aircraft model, generally an object like a wing is composed of other parts. 5.2 Getting your objects out of Blender and into Flightgear.