Blender To Unreal Exporting

This page will cover the basics of exporting a mesh to either the UT 3 editor [.ase exporting] or the UDK editor [.fbx exporting].  There are 3 factors that will determine the information on this page.  They are the version of Blender, the version of each exporter, and my knowledge.

Keep in mind that this page covers what the exporters can do.  This might not be the same thing as what you should do, to have an optimized mesh.

UT 3/UDK ASE Exporting

Using Blender 2.60 with MCampagnini’s ASE exporter (v. 1.4.1).  Much thanks to MCampagnini  for taking the time to update this script.  If you notice any bugs, please contact MCampagnini at his site.

• Collision Models [Works]
  • Collision models must have a naming convention that includes “UCX_” in the name.  Example: “UCX_1″, “UCX_2″, “UCX_3″.  These shapes need to be convex in nature and should be as simple as they can be.
  • They need to be selected with the model when exporting.
  • They do not need a material, texture or UV map assigned to them!
• File Extension [Info]
  • The exporter will automatically place a “.ase” extension on your file name.  If you accidentally erase it, you will need to add “.ase” to the end of your file name for it to save in the proper format.  Example “cube.ase”.
  • You can overwrite existing files.
• Multiple Materials [Works]
  • You need to create the number of material slots you want and create a unique material name for each slot.
  • Each material needs a unique texture name and assigned a unique image file to each texture slot.
• Multiple UVs [Works]
  • You can add multiple UVs, as needed.  Usually, one is used for the visible textures, while the second one is used for light mapping/shadows.
  • I have received best results, for a UV Light Map, by unwrapping the mesh manually and not using the “Lightmap Pack” option from the Unwrap menu.
• Scale [Info]
  • By default, the exporter will scale your mesh by 16.  Depending on your grid settings and how you built your model, you may want to change this.
  • You can permanently change the default value by opening the script in note pad.  Search for “ASE_SCALE = FloatProperty(name=”Scale”, description=”Object scaling factor (default: 16)”, min=0.01, max=1000.0, soft_min=0.01, soft_max=1000.0, default=16.0)”.  Change the numerical value at”default=16.0″.  Save the file.  You will need to deactivate the script and reinstall it.
• Smoothing Groups [Works]
  • Version 1.3.0 uses any edges marked as “sharp” to determine if a smooth group should be made.
• Triangulation [Info]
  • By default, your model will be triangulated before it is exported (you can uncheck the “Auto Tris” button to prevent this) .  When you return to the model, the quads will be triangles.  A model must be triangulated before it gets imported into the editor.
  • You can save a copy of the file, duplicate the mesh before exporting, or convert your triangles back to quads (which may not always return it back properly before it was exported).
• UVs [Info]
  • This is a requirement for all meshes in order to properly display a texture/material in the editor.
• Vertex Painting [Works]
  • You can use up to 3 textures (to my understanding).  This can be used to create terrain/landscape.  The mesh must have a decent number of vertices for it to be painted properly.
  • Currently, for vertex painting to work, you need to have 2 UV maps.

UDK FBX Exporting

Using Blender 2.57 with the stock FBX exporter.

• Collision Models [Works]
  • Collision models must have a naming convention that includes “UCX_” in the name.  Example: “UCX_1″, “UCX_2″, “UCX_3″.  These shapes need to be convex in nature and should be as simple as they can be.
  • They need to be selected with the model when exporting.
  • These do not need any specific material or UV mapping assigned to them.
• File Extension [Works]
  • You don’t have to add the .fbx extension when exporting the file.
• Multiple Materials [Works]
  • You need to create the number of material slots you want and create a unique material for each slot.  You don’t have to assign a image for the material.
• Multiple UVs [Works]
  • You can add multiple UVs, as needed.  Usually, one is used for the visible textures, while the second one is used for light mapping/shadows.
  • On the UV Mapping menu (pressing the U key in edit mode), there is an option, Lightmap Pack, which can be a quick way to create a UV map for light mapping.
• Scale [Info]
  • By default, the exporter will scale your mesh by 1.  Depending on your grid settings and how you built your model, you may want to change this.
• Triangulation [Info]
  • The model retains the same faces it had before it was exported.
• UVs [Info]
  • This is a requirement for all meshes in order to properly display a texture/material in the UDK editor.
• Vertex Painting [Works]
• You can use up to 3 textures (to my understanding).  This can be used to create terrain/landscape.