Hello! I am working on a custom character rig in Blender that uses multiple meshes bound to a single Armature. I have applied all transforms in Blender before exporting, but I am running into two persistent issues when importing the FBX into Roblox Studio using the 3D Importer.
The Issues
Issue 1: RootPart Displacement (Geometry Offset from Collision)
The Problem: The RootPart behavior is broken. The actual visual geometry of the model is placed much higher than it should be, while the physical collision box stays lower down on the ground.
What I’ve Tried: I tried adjusting the HipHeight property in Roblox Studio, but it did not fix the offset. All transforms (Ctrl + A → All Transforms) were applied to both the meshes and the armature in Blender prior to export.
Issue 2: Eye Bones / Visual Bug with Face Rigging
The Problem: I cannot animate the eyes because the eye bones or their associated geometry are glitching/not showing up correctly after import.
Details: I am not using dynamic heads or Cage Mesh Editing (Dynamic Wrap/Cages). All facial and eye movements are done purely by hand via classic bones. This rig utilizes multiple meshes under one single Armature, and I suspect Roblox is struggling to map the bones to these separate mesh parts correctly.
I haven’t found any reliable solutions for rigs that use multiple distinct meshes on one Armature with hand-keyed bone animations for the face.
How can I force the RootPart and the geometry to align perfectly upon import?
Is there a specific hierarchy or naming convention required when rigging multiple meshes to one skeleton so that small facial bones (like eyes) don’t glitch out?
Any help or workflow tips would be greatly appreciated!
The character is originally designed to be on all fours. The topology and mesh are specifically built around this unique posture, so forcing him to stand vertically wouldn’t work well with his model structure. He is still fully intended to be a playable character in this stance.
Also, as I mentioned in the main post, I have already applied all scales and transforms in Blender before exporting.
normally when a root part is small like that it could be many reason one reason i can think of is your model scale is too large. try exporting it from blender using the 0.01 or 0.1 instead of 1.0
i made a dummy model to test what u trying to do it should look something like this if correct
The problem is I didn’t follow the exact hierarchy Roblox requires for custom rigs. Right now, there is a main bone (Spine1) that rotates the model itself. If this is causing the issue, could I just add a central bone to act as the primary RootPart?
you do not need the roblox hierarchy for a custom avatar ,
but if your character have almost the same limbs as it yes you should use the roblox hierarchy to make it easier and less error prone and you want it to be a ugc item
