Howto:Work with AC3D files in Blender
Many FlightGear aircraft modelers prefer Blender as their 3D-modelling editor. FlightGear primarily uses the AC3D file format (
.ac) to model aircraft, scenery models, and many other things. There is good support for the import and export of the AC3D file format from Blender. This page gives an overview of those options.
Blender versions 2.4 and older
For these versions, Blender supports both the import and export of AC3D files out of the box. Just go into user preferences and enable the addon scripts.
Blender versions 2.5 to 2.62
For these versions you can use one of these scripts by Majic79:
- Version for Blender 2.59 (repository) (ZIP file download).
- Version for Blender 2.60 (repository) (ZIP file download).
- Version for Blender 2.62 (repository) (ZIP file download).
Blender versions 2.63 and later
For version 2.63 onwards you have a choice of several scripts.
Current maintainer: User:Necolatis
Tested with Blender version 2.63 to 2.78a
- Before you export a model with this addon, make sure that you set the UV map and texture inside the material, not just inside the UV editor. See the video tutorial here.
- Before you export make sure to exit Edit Mode or some of your last changes won't be exported.
- Inside Blender when you want to see the textures, be sure to set the shader to GLSL (or for 2.7+ just set view mode to materials). Alternatively set textured solid in solid view.
- To see textured surfaces as they will be shown in Flightgear, go into the material texture and set the blend type to "Multiply" instead of the default "Mix" (the importer will also do this automatically). An example plane that will look very different if this is not done is the FGAddon aircraft ASK-13, notice the wingtips.
- If you wonder where to put the scripts you could open blender's user preferences (CTRL ALT U, or File->User Preferences) tick e.g. Import/Export and extent the informations concerning an existing script. Usually this throws the path. For Ubuntu 14.04LTS/Blender 2.79b e.g. it's: /usr/share/blender/scripts/addons/.
- Be aware that Blender only has greyscale for emission and ambient colors. If you want to export/import a color for those, import/export options gives you capability to choose to use Blenders mirror color for that.
- The importer will not fail if it does not locate a texture, instead it will issue warnings. Pull down the top bar to see if there was any, they will be orange lines.
- The exporter will not fail if it tries to save a texture without data, instead it will issue warnings. Pull down the top bar to see if there was any, they will be orange lines. Notice that since AC3D only support 1 texture per object, if multiple textures are attached to an object in Blender the last of the textures that has any data, if any, will be the one that get exported, but it will still warn about the missing data in the others, so take care.
- Orientation: The default settings in the plugin correspond to the FlightGear coordinate system (-X forward and Z up, also see: Howto:3D_Aircraft_Models). The default settings are: Forward -Z and Up Y.
You can report bugs with the addon here, but please include problematic .ac/.blend files and their textures.
Notice that the above link is to Necolatis (Nikolai) latest version, as the Majic79 github hasn't kept up with the updates and seems dead.
Mr. No addon
- When exporting with this addon, make sure you set the texture inside the UV editor.
- When using this script, it is very important that everything is textured. The addon will silently fail if this is not the case.
- This script does not work reliable when nested groups are being used in the imported AC3D model (example here).
- The importer cannot handle the token 'subdiv', its just ignored.
- The exporter does not always export the rotations/location matrix of objects correctly.