HowTo/Export from Blender using FBX

Revision as of 13:35, 6 December 2016

(Work in progress)

This is very much a work in progress as:

(1) the author learns more about the process, and
(2) N3V are exploring the FBX format.  Please contact the author if you have something to contribute.

Introduction

This guide provides information for the export of FilmBoX (FBX) files from Blender.

Versions

The FBX format

A brief discussion on the FBX format history can be found here . FBX can be exported either as an ASCII (i.e. human readable) file or in binary format. TANE will only recognise the binary format.

Blender and FBX

Blender is capable of both importing and exporting FBX. The Blender exporter does not export all possible object attributes and it is likely that TANE will not recognise all those attributes that are exported. The Blender documention contains a list of attributes that are exported.

Included in this guide is a list of attributes that have been observed as exported and treatment/acceptance by TANE. The list is incomplete and so is a work in progress.

Skills Required

For this version of the guide, it is assumed the user has some knowledge of the use of Blender and an understanding of the Trainz asset creation process.

Exporting a mesh object from Blender in FBX format

The FBX exporter addon must be enabled in User Preferences.

Select File->Export->Export FBX and the FBX export panel will show in the bottom left hand corner and should look like the following picture. The panel contents vary significantly between the Binary export version and the ASCII export version so make sure you have Binary selected.

The Main Menu

FBX Main Menu

• Ignore the Operator Presets for now.
• Ensure FBX 7.4 binary version is selected.
• The Main/Geometry/Armatures/Animation buttons provide menu options for the item selected. Select the Main option.
• Selected Objects. This option needs careful consideration. Unlike the Blender XML exporter, the FBX exporter will export all objects in all layers

which is probably undesirable in many cases and particularly if you have different LOD models in different layers. So, first select those objects within Blender that you want to export and then select Selected Objects in this panel.

• Scale. Leave the Scale value as 1.00 and deselect the small icon to the right of the Scale value.
• Forward and Up. Set these to the values :Y forward and Z Up.

The options below are multi select (i.e. you can select more than one). For the time being just leave Mesh selected.

• Leave the Experimental and Custom Properties as deselected.
• Leave Path Mode as Auto and Batch Mode as Off.
• Choose the FBX filename and export using the Export FBX in the top right hand corner. There is no exporter log.

Tip

You can save your preferences for a given situation by clicking on the plus button (+) next to Operator Presets. This is particularly useful for animation.

The Geometry Menu

FBX Geometry Menu

• Leave these values as shown. (more testing required ;o) )

The Armatures Menu

FBX Armatures Menu

• Leave these values as shown. (See animation section)

The Animation Menu

FBX Animation Menu

• Leave these values as shown. (See animation section)

Config.txt

Setting up the CONFIG.TXT

The only changes to the config.txt are in the mesh table. The mesh entries for FBX files now have a "trainzmesh" extention as per the following example:

 mesh-table {
   default {
     auto-create                           1
     mesh                                  "my-mesh.trainzmesh"
   }
 }

Note that for the LM.TXT Level of Detail (LOD) you can still use the LM convention but the LM.TXT file must refer to trainzmesh files.

Files Created

Mesh Files

The file my-mesh.trainzmesh is created during the asset commit. Currently the FBX file is not deleted but bundled into the asset. Since the FBX format is readable by 3D modelling tools, you may want to remove any FBX files from assets uploaded to the DLS or other web sites.

Texture.txt Files

You can provide your own texture.txt files (advisable) or let the commit process create them for you. The commit process will create suitable files, such as those required for normal maps, but you can provide your own if you have special requirements.

Warning: If you get odd effects with your textures, check the associated texture.txt file first. The FBX importer tends to add an "alpha=" line even though no alpha option has been chosen.

Warnings and Errors

The TrainzDev team are reporting issues back to N3V and many problems have been fixed. The following is provided to assist creators.

Materials

This section identifies the material options used by the FBX exporter. For detailed descriptions on how Trainz uses material types see Material Types and the child pages detailing different Trainz material types.

The exporter treats material options based on the chosen material shader model. Even though Trainz uses its own shaders, it may be worthwhile selecting different shader models in Blender to see the effect. In particular, choosing the Phong model for the specular shader will enable the export of a number of extra material options. These may, or may not, actually result in observable changes in Trainz.

The FBX exporter uses the following material options:

Be wary of checking Shading->Shadeless as this stops the export of several attributes including: Specular Color, Specular Factor, Shininess Exponent, Reflection Color, Reflection Factor, Specular, and Shininess.

In summary, material values you can play with in any material include:

• Diffuse colour
• Diffuse specular
• Transparency
• Specular colour
• Specular intensity
• Specular hardness
• Shading Emit
• Mirror
• Ambient (in World)

Textures

This section identifies the texture options used by the FBX exporter. Very few of the available options are actually exported and the only exported item relevant to normal/bump maps is the Mapping->Coordinates value. In practice, this isn't an issue as test assets using Trainz bump mapped materials work fine. You might need to provide your own texture.txt files when normal maps are required.

The FBX exporter uses the following texture slot options: