VFX export options

Export high-detail models with the VFX export options. Based on the format selected, these exports can support wind animations, growth animations, mesh unwrapping, and skeletal skinning.

To export a model for VFX, select File > Export mesh then choose the VFX export type.

For command line export options, refer to Export from the command line.

Export type

Type	Description
Games	Export a model with options optimized for games. Refer to Games export options.
VFX	Export a model with options optimized for VFX.

Preset

Preset	Description
Maya	Optimize the export for Maya.
3D Studio Max	Optimize the export for 3ds Max.
Houdini	Optimize the export for Houdini.
Blender	Optimize the export for Blender.
Cinema 4D	Optimize the export for Cinema 4D.
FBX	Export a generic .fbx model.
Alembic	Export a generic Alembic model.
USD	Export a generic .usd model.
Growth	Export a generic Alembic model with growth animation.
Wind	Export a generic .fbx model with wind animation.

Preset options

Control	Description
Save new preset	Save the current export settings as a new preset.
Edit preset name	Edit the name of the current preset.
Delete preset	Delete the current preset.
Load options	Load previously saved export options from an .ini file.
Save options	Save the current export options to an .ini file.

Options

File type

Currently, the SpeedTree Modeler can export meshes in:

Autodesk FBX (.fbx)
Wavefront OBJ (.obj)
Universal Scene Description (.usd)
Alembic IO (.abc)
SpeedTree Pipeline SDK (.ste)
SpeedTree Raw XML (.xml)

FBX and OBJ are the most well-supported formats in a variety of third-party applications. USD and Alembic are used more for exporting animations, especially growth animations where the topology changes over time. Wind animations can still end up being a smaller size than in FBX, if that is a concern.

Raw XML files are used only in custom pipelines that require extra vertex data from SpeedTree that is not available in other formats.

Grouping

On export, the geometry in a tree can be grouped in different fashions, depending on how the final mesh will be used or modified in an external application.

Hierarchy

Grouping by hierarchy sets the level in the tree under which the tree will be split apart. For example, a level of 0 means the entire mesh in one group. A level of 1 means the trunks of the tree will each be in different groups with their children (in most cases of simple trees, this will be identical to level 0 since there is only one trunk). With a level of 2, the trunk will be in one group and then each major branch will be in a group with all of its children.

Three trees. One shows a level 0 hierarchy and is all one color. Another shows a level 2 hierarchy and the trunk and various groups of branches are different colors. The third tree shows a level 4 hierarchy and the trunk and small groups of leaves are all different colors.

When grouping by hierarchy, the pivots and bounding boxes will be set accordingly. Because of this, you can move and rotate a single branch and all of its children easily if you export grouped by hierarchy at level 2.

Material

Grouping by material will do just that, group the geometry by the material it uses. Unwrapping the mesh and using variations may change the final material associations, and thus the grouping.

Geometry type

Grouping by geometry type will make mesh groups based on the type of tree geometry it is - branch, leaf, mesh, etc.

Generator

Grouping by generator will group geometry by the generator used to create it.

Include

There are a variety of extra things you may include in the mesh during export.

The availability of these options changes depending on the export format.

Geometry

Includes the actual 3D geometry being exported. Disable this only if you need one of the other includes, like Spines, generated with different settings from the geometry itself.

Available for FBX, Alembic, USD, and XML.

Bones/skeleton

Includes the skeleton created in the SpeedTree Modeler and smoothly skins the vertices to the correct bones.

Note

Enabling bones with hierarchy grouping will move the origin of each group to the origin. This is to prevent errors occurring with skeletal deformers in some 3rd party applications.

Available for FBX and XML.

Leaf references

This option includes null references in the correct position and orientation for each leaf. These can be used to populate the leaves with higher quality meshes at runtime.

Available for FBX, Alembic, USD, and XML.

Branch spines

Includes a spline down the center of the branch, useful in some kinds of skinning.

Available for FBX, Alembic, USD, and XML.

Vertex blends

Vertex blending is used on small pieces of geometry that need to blend, such as the intersection of a branch to its parent or stitches to a parent mesh. This is done using vertex alphas to fade it out.

Separating vertex blends pulls the blends out into a separate object.

Available for FBX, Alembic, USD, XML.

Transform

These options modify the output size and geometry of your model. You can keep the current scene unit, convert to a different unit, change the scale, or flip and rotate the model for a particular coordinate system.

Textures

These options control the format and size of the exported textures.

No matter the format chosen for export, many of the same steps occur when dealing with textures. All needed textures are exported, per-material, and all the texture adjustments made in the Modeler are baked into the final texture. Material variations are handled by baking new versions of the maps into a new material used on the tree, so nothing additional needs to be done elsewhere to support them.

Additionally, a SpeedTree material file (.stmat) is saved next to the exported mesh that contains all the information about the materials coming from the SpeedTree Modeler. Different formats have different ways of specifying materials, and some do not have the options to fully recreate SpeedTree materials elsewhere. To combat this, importer scripts for Maya, Max, Houdini, etc. read the ".stmat" file and use that information to recreate the materials as closely as possible.

Animation

In formats that support it (FBX for wind, Alembic for wind and growth), you can include animation. This animation is saved as a point cache file. Depending on your tree's complexity and length of the animation, computing these caches may take a long time and create large files on disk.

Loop

SpeedTree wind tends to have many, many different parts moving independently at different frequencies. Due to this, it can be difficult to make a looping animation seamless. In SpeedTree 9 or later, a "Loop" option is available that attempts to allow this by using geometry morphing/interpolation. An extra portion of wind animation is computed before the exported animation, and is then interpolated to at the end of the export, providing a seamless loop transition.

Note

When wind speeds are very different at the start and end of the animation (due to use of gusting or timeline wind), the loop seam can be more noticeable. Maintain similar wind situations at the start and end of the animation for a more seamless transition.

A diagram of a seamless wind animation loop. It begins with the wind animation at the Simulation Preroll, goes to the Loop Computation, and then to Exported Animation. There is an arrow that goes from Loop Computation to the end of the loop that points to Interpolation to Match Beginning.

Format-specific

When exporting an animation, different cache formats have options that will appear in this section.

Extra

Control	Description
Show summary	Shows a summary of the export settings when the export completes.
Skip texture save	Doesn't save the textures to disk.