Exporting Rigged Models to Roblox
Most people who try to get a Blender rig into Roblox end up with broken animations or mesh deformation issues. The pipeline exists, but it's not clean. I spent about six months debugging this before I had it working reliably. A Roblox Blender Rig is a character model set up in Blender that follows the R15 or R6 skeleton structure Roblox expects. The rig contains bone joints mapped to the correct hierarchy, weights painted to the mesh, and usually a rest pose ready for animation or immediate export. It's not just a model with bones — it has to conform to Roblox's rig naming conventions and joint structure or the model won't animate correctly once in-engine. The two skeleton types matter here. R15 has fifteen bones and supports full limb rotation. R6 has six bones — torso, head, and paired upper/lower limbs. Most of the community work in R15 these days because it gives you actual control over arms and legs separately.
The Workflow
Start with a clean mesh. Apply all transforms — Ctrl+A on everything — before you build your rig. Rotations at zero, scale at 1.0. If you skip this, the exporter will produce garbage and you'll waste an hour wondering why the character is stretched diagonally. Set up your armature with the Roblox joint names. You can do this manually or use the Roblox Blender plugin, which auto-names the bones. I prefer the plugin for new rigs because it handles the hierarchy correctly out of the box. The manual approach works fine if you already know the bone list by heart. Name your vertices carefully. The Roblox exporter requires vertex groups named exactly like bone names. A common mistake is naming a group "UpperLeg_L" when the bone is actually called "LeftUpperLeg". The weights won't transfer and your mesh will float off the skeleton during export.
Parent the mesh to the armature using Armature Deform with Empty Groups. Then assign weights with the weight paint tool. Keep the default weight at 1.0 for vertices directly on a bone, and blend across the joint areas so there's no sharp clipping when the model bends. When everything's weighted, switch to pose mode, pose a simple T-pose or A-pose if needed, and export as an .fbx file. Make sure you check "Selected Objects" and "Apply Transform" in the export settings. Set the forward axis to -Z and up axis to Y. That's the standard Roblox convention and if you get it wrong, the model will spawn rotated ninety degrees in the game. Import the fbx into Roblox Studio through the Toolbox or by dragging it into the Explorer. It should appear as a rigged mesh that plays animations correctly.
Get the Full Details
My Experience Breaking This On Purpose
Once I tried to animate a character with a cloth cape using vertex groups and it completely tore the mesh apart during export. The cape vertices had weights assigned to the hip bone and the shoulder bone simultaneously, and when the character walked, the fabric geometry snapped between two positions instead of deforming smoothly. I ended up separating the cape into its own mesh object, parenting it under the root bone without deformation, and just letting it hang statically. It looked acceptable for a first pass. Later I learned to use shape keys or separate armatures for secondary geometry instead of baking it into the main weight map. Another issue I ran into: Roblox's rig doesn't supportFK/IK switching natively the way Blender does. If you set up an IK rig in Blender and export it, the IK constraints don't carry over. The exported animation freezes at whatever pose the bones were in at the moment of export. You have to bake all IK-driven animation into pose data first, then export. This took me about three weeks to figure out because the documentation doesn't mention it anywhere.
Counter-Intuitive Things Nobody Teaches
First: do not delete history in Blender before exporting. The Roblox import pipeline sometimes depends on modifier stack information, especially for subdivision surfaces. If you apply a subdivision modifier too early, you'll lose edge flow control and the mesh will look blocky at animation joints. Keep the subdivision modifier unapplied and set it to render at a higher level than viewport. Export at render resolution, not the lower preview level. Second: the bone length in your rig affects how animations interpolate. Short bones with long limb segments create unnatural bending because Roblox's animation system interpolates along the bone axis. I learned this the hard way when a character's elbows bent backward. The fix was simply extending the bone length to match the actual limb proportion. It sounds trivial but most beginners never think about it because Blender's default armature generator makes bones short by design.
Where This Pipeline Breaks Down
The biggest limitation is that Roblox does not support custom skeleton structures. You cannot add extra bones for facial rigs or flexible spines. If you need expressive animations beyond what the standard rig provides, you're stuck. The workaround is layering meshes — a base body rig for body animation and a separate facial mesh that responds to limited bone triggers through BillboardGuis or animation state swapping. Another issue is file size. Every vertex group and bone adds to the memory footprint. A fully weighted R15 character with detailed mesh geometry can easily hit 5 to 10 MB per model. Roblox compresses assets on upload but there's still a soft limit around 250 MB per place. If you're building a game with dozens of rigged characters, you'll run into this ceiling quickly. The solution is aggressive LOD simplification — reduce vertex count per mesh and merge low-detail characters into shared resources. If you need something more complex than standard character animation, consider using RigForge or a third-party rigging plugin instead of building from scratch. They handle the bone naming, weighting presets, and export formatting automatically. It saves roughly forty minutes per rig compared to manual setup, which adds up fast if you're producing a lot of content.
