FBX Frequently Asked Questions

Q: Can I import any FBX files I own?

A: In theory all FBX files should be supported. However, different applications store things in FBX files differently so results may vary. We have tested FBX files created in Blender, 3D Studio Max, Maya and Sketchup. If you find an FBX file that does not import correctly please let us know. We’d like to investigate.

Q: Can I import any FBX files I find?

A: We have tested FBX files from across the internet, including sites like free3d.com, with good results. Keep in mind that most FBX files will need to be imported as furniture items, as they have not likely have been built on top of the IMVU skeleton. However, it is up to you to ensure that you have rights to use these products in IMVU. If you choose to resell them on IMVU that will require additional rights. All virtual products must follow the IMVU copyright and trademark rules. Copyright and Trademark Infringements

Q: Are there any known limitations with IMVU’s FBX support?

A: Currently we do not know of any limitations on FBX files other than those caused by the tools that created them. To create avatar animations, avatar clothing and full IMVU avatars you will be required to build on top of the IMVU avatar skeleton. However, other animations and “characters” can be imported as furniture and should work nicely.

Q: Why does my FBX clothing screw up the avatar when I import it?

A: When importing an avatar, an avatar’s clothing or avatar animations it is required that your FBX be built on top of the full IMVU avatar skeleton. If any bones, vertex groups/weights are missing, or misnamed, then mesh weighting and skeleton animations will not match, stretching and bending your avatar in directions you did not intend.

Q: I imported the sample avatar FBX but the avatar looks all wonky. Why is that?

A: When you import the IMVU provided sample file for an avatar you first need to derive from product 80 (for the female) or 191 (for the male.) Then, once imported, you need to edit the config tab entry for skeleton panels and set your skeleton to the IMVU skeleton. For a female avatar that is Female04_Anime01_SkeletonMASTER.xsf. This ensures that you are bound to the correct IMVU skeleton.

Q: After importing, my skeleton is still messed up. Why is that?

A: When using Blender, there are 2 distinct paths you need to take to ensure you are building off the correct skeleton. If you are creating animations or an avatar then you need to use the skeleton that exists in a Blender starter file that is built for animations. (Examples: Avatar 80 Female Full Body-v01.blend, Avatar 191 Male Full Body-v01.blend or Animation Female Monster Animation-v01.blend). If you are creating clothing then you need to use the skeleton that exists in a Blender start file build for clothing. (Example: Bottom Female Denim Jeans-V01.blend). And remember, if you are importing an avatar or animation then you still need to switch to the correct skeleton after import, as noted above.

Q: How can I leverage an FBX file that was not built on the IMVU skeleton?

A: Many FBX files can be imported as furniture or accessories. These have fewer restrictions since their skeletons do not need to match the IMVU skeleton. For example, you could import a frog and make it into jumping furniture in a room, or make it into a pet that sits on your avatar’s shoulder and catches flies.

Q: Are double sided textures supported?

A: IMVU can do this by default using the “two-sided” material parameter, rendering both sides of a mesh using the same texture (duplicates and inverts the original). To achieve doubled-sided meshes using different textures you must duplicate the desired surfaces, invert them and apply another asset before export.

Q: I can export ascii and binary FBX files, are both supported?

A: The FBX import feature can import both ASCII and BINARY versions of the format however, preference is for BINARY to ensure feature completeness (the export/import of meshes, skeletons, animations etc.).

Q: When I import my FBX files the mesh is too big/small, why is that?

A: The size/scale of the default avatars is relatively large compared to the defaults other applications may use. This has the inadvertent consequence of meshes being too small or too big depending on those differences, necessitating some adjustment and rescaling to ensure a proper fit. It is common for Blender files to require you to set the import scale to .01. (Note: the blender samples we provide were exported from blender at the .01 scale, so you do not need to adjust the scale when importing those files.) We have found the following scale factors to be common.

  •  – Sketchup: import with a scale of 20
  •  – Maya: import with a scale of .01
  •  – 3ds Max: import with a scale of .01
  •  – Blender: import with a scale of .01

Q: When I import my FBX mesh it’s facing the wrong way/aligned incorrectly, why?

A: The way objects and scenes are orientated is not universal between 3D applications. IMVU uses a 3DS Max global orientation which uses “Y” as “up”, not “Z” as might be used elsewhere. If your model is not rotated correctly try opening the file in Blender and export from blender with different export main settings for “forward” and “up” and the export armature settings for “Primary bone axis” and “Secondary bone axis”. Typically “Y” for “Up” works for us. Alternatively, we have provided a feature that allows you to alter the Axis of your model during import. The axis changes you apply here will affect the avatar’s skeleton, animations, meshes, etc. We suggest the following flow for best results:

  • – Import your model with no changes to the Axis. This works 75% of the time.
  • – If your model is “laying down”, re-import it, changing just the Up Axis value and retrying until you get it right. (If the model is facing down then try a negative value like -Z.)
  • – Once your avatar is facing up correctly you can then re-import with different Front Axis values until it is facing the desired direc


Q: Is there a limit to how big my FBX can be, number of surfaces/textures/MBs?

A: The eventual product file uploaded to the catalogue and distributed to users should be kept as small as possible. This will typically mean meshes be optimised (as few polygon/triangles as possible) and image assets be no larger than 512 pixels in any one dimension (reuse images where possible and scale them relative to the amount of detail they are expected to show – smaller images for smaller items). Remember, many customers are moving to the IMVU mobile offerings. These customers greatly appreciate fast, optimized products.

Q: Can I import multiple FBX meshes into the same project/product, is there a limit?

A: Yes, multiple meshes can be imported at the same time, each is defined and given its own “meshes” entry in Create Mode. The upper limit is 99 for normal product development but can be reached quickly if exporting individual blades of grass for example, reasonable usage is therefore suggested.

Q: Can I add an FBX mesh to a project with Cal3D meshes?

A: The FBX import process creates a series of compatible XML files – the project folder contains either/or/all *.xsf, *.xmf, *.xaf, *.xrf, *.xpf after an FBX files import. These should then be usable just like other CAL3D assets.

Q: I have an old Cal3D project, can I assign textures from that to an imported FBX?

A: Because the FBX import process creates standard CAL3D XML files (xmf, xaf, etc.) that are stored in the item project folder, any previously assigned texture or material assets should be re-assignable. In Create Mode some minor Texture Assets property editing may be necessary.

Q: Can I (still) import sound files and use them in my FBX project/s (like I could with Cal3D?)

A: Once FBX files have been imported into a project they can be assigned as normal (as was previously possible using CAL3D). The FBX import and conversion feature should have no effect on *.ogg audio files, which can be assigned as normal.

Q: How can I successfully export from Blender and get the settings correct?

A: Blender has many export options. Here are the settings we have found to work best:

  • – Only export the skeletons and meshes you need
  • – Change the Blender Units settings to .01 (Results may vary, but typically blender files are 100 times larger than IMVU expects. This can also be changed during the fbx import process if necessary.)
  • – Under the tab “Main”, check “!EXPERIMENTAL! Apply Transform”
  • – You may need to play with your “Up” settings, this can take some trial and error but usually “Y Up” is correct
  • – Under “Armature” deselect “Add Leaf Bones”. This setting will not be saved, so you need to deselect it each time you export

Q: How can I successfully export from 3D Studio Max and get the settings correct?

A: 3ds Max has many export options. Here are the settings we have found to work best:


You can use 3Ds Studio Max 2018, but be aware that we have seen some FBX exports that worked in 3D Studio Max 2017 crash in 3Ds Studio Max 2018 Select the bones you wish to export (Do not export bones that exist only for building animations. In the IMVU sample max files these are typically named with the starting text CTRL_ or ALIGN_)

  • Choose export-fbx and give the file a name
  • Make the following settings:
    • – Geometry->Check Smoothing Groups
    • – Animations->Check animation
    • – Animations->Deformation->Check skin
    • – Animations->Deformation->Uncheck morphs
    • – Advanced options->Axis conversion->Up Axis: Z-Up
  • FBX File Format can be ASCII or Binary
  • Hit OK


Q: How can I successfully export from Sketchup and get the settings correct?

A: Sketchup can be a nice tool for creating furniture, attachments and rooms for IMVU. Here are some tips for using Sketchup. The free version of Sketchup will not export to FBX files. However, you can export to Collada files and convert those to FBX files with the free Autodesk conversion tool FbxConverterUI https://usa.autodesk.com/adsk/servlet/pc/item?siteID=123112&id=22694994 for testing.

Please keep in mind that publishing products for sale that were created in Sketchup requires that you have a license to use Sketchup Pro. In some cases, Sketchup will rename important bones when exporting as FBX, thereby breaking functionality. (For example, furniture.Wall.01 can get renamed to furniture_Wall_01_1).

You can see the bone names after loading the FBX by expanding the “skeleton” bar in the FBX importer. To work around this issue, export the file from Sketchup as a collada file and convert it to FBX using the Autodesk FBXConverterUI> tool, as noted above. The Sketchup export settings we enable for Collada are shown below (we leave the others unchecked):

  • – Triangulate All Faces
  •  – Preserve Component Hierarchies
  •  – Export Texture Maps

Sketchup files are typically 20 times too small for IMVU. You can change the scale of your model in Sketchup, or you can change the scale from 1 to 20 during the FBX Import process in IMVU. IMVU now handles cases where color definitions have been used instead of textures. If your product contains references to color values then the FBX Importer will generate small image files of the color desired and it will use those as the texture file for your product. It is encouraged that you gather your Sketchup meshes into Sketchup Groups. During import, if we detect groups then we add the meshes of that group into sub-meshes. This helps you avoid hitting the 100 mesh limit that IMVU imposes for each product.

Q: How can I successfully export from Maya and get the settings correct?

A: Maya is a great tool for creating IMVU content. Just export an FBX file from Maya and give it a try. Remember to check the Animations checkbox if you wish to include animations. We have had success with FBX version 2018, but other FBX versions should work as well.

Q: I imported a Sketchup model and half of it is missing. What happened?

A: It is common in Sketchup to create “components” and reuse them in your model. For instance, you may create a “table leg” component and use 4 copies of that let to make a table. The FBX Import feature has trouble differentiating between the different copies of the component and ends up only displaying one of them. A temporary fix for this issue is to “explode” the components in sketchup then regroup them before exporting your FBX file. We are working to remove this limitation for a future release.

Q: When creating attachments, what are the names of the bones I can attach to?

A: Here is a hierarchical view of the IMVU skeleton: Avatar Skeletal Hierarchy

Q: Can I create a bone in an FBX file that will create IMVU lights for me?

A: Yes. If you name the bone correctly it will be detected as a light. Please keep in mind that the downloadable client only supports RGB colors. Spot lights and other features will only show up on IMVU Mobile and the IMVU Next Website. Here are the parameters and an example. Light bone names:

  • lightOmni              – a light that shines in all directions
  • lightPoint              – same as lightOmni
  • Omni01                 – same as lightOmni
  • lightTarget            – a light that focuses in one direction in a cone, default soft value is 1.0, default cone value is 15.0
  • lightDirectional     – a light that focuses in one direction like the sun, default soft value is 1.0
  • For all light types the default rgb value is 777777
  • For all light types the default bright value is 1.0
  • For all light types the radius is 30

Light parameters:

  • rgb=        – apply a color to the light in the range 000000 to FFFFFF (RRGGBB)
  • bright=   – define the light’s brightness as a float from 0.0 to 1.0 (1.0 is the brightest)
  • cone=     –  This value is a float value from 0.0 to 180.0. It is meant to represent the beam angle (in degrees) of the Light.
  • soft=        – This value is a float value greater than 1.0 (1.0 is the sharpest)
  • radius=     – The effective distance of the light (default is 30)

Full Example: lightTarget:rgb=AAAAAA:bright=0.5:radius=20:cone=90:soft=3

Updated on July 21, 2023

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