There is a plugin for Roblox that is able to export any Roblox rig into Blender and generate a Blender Armature or rig equivalent to the Roblox one using the accompanying Blender addon. Then, in the thing called Blender, the animation is able to be designed. When it is done, the Blender addon is able to be used to generate Roblox animation data equivalent to the animation designed in Blender. With the help of Roblox plugin, this one is able to be imported back into Roblox again.
If you want to install Blender Rig Exporter/Animation Importer, you can just go to the official website of Roblox and head to the Search bar. Please type the keyword “Blender Rig Exporter/Animation Importer” to be able to see the result. When you are in the page of the tool, you will be able to see the Install button. All that you need to do is to press that button and the process of installing will be started immediately.
Blender Rig Exporter/Animation Importer is the one that was made by Den_S. Since the first time its release, it has been installed 22,234 times, has been favorited 634 times, and has been liked 104 times. The last update of the plugin is on October 10, 2019. How much does it cost to get this plugin? Fortunately, you do not need to spend any as it is 100% free.
Aside from the Roblox plugin called Blender Rig Exporter/Animation Importer, you will also need to install Blender addon. There are some types of Blender addon. The most recommended one is Blender 2.80. You are able to install Blender addon through Edit > Preference > Add-ons > Install from file > (choose that one).
This paragraph consists of the very basic how-to-use guide for Blender 2.80. in Roblox, the first thing that you have to do is to enable the plugin, click a Rig. If successful, the GUI will show up. Then, click Export rig, save the .obj file somewhere. In Blender, you need to go to File > Import > Import the .obj file. In Blender, in the right panel in the 3D view (you are able to press N if visible), you need to open the Rbx Animations tab, and then click Rebuild rig. Please keep in mind that bones should be generated after clicking this button. The next thing that you have to do is to choose the created Armature, enter Pose mode (Tab > Pose mode). Afterward, move or rotate a bone and then create the keyframe. You have to make sure to choose the LocRot keying set or enable auto keying. When you are done, create another keyframe at another timestamp. Then, click Export animation in the right panel. This one will copy text to the system clipboard. In Roblox, press “Load large animation”, paste the text copied to the system clipboard. By doing the step, the animation will now be loaded in Roblox. The last thing that you have to do is to click “Upload animation” in order to upload it to Roblox as Roblox animation.