Export Your Avatar from Worlds

The main tool you will need is Sgeo's RWX Exporter which only works on Worlds Version 1904.

You will need to go to an empty room. I have created a World for this purpose here: http://files.worlio.com/users/sl0nderman/worlds/empty.world. This is simply a default world with all the walls deleted. This way, only the avatar will be captured.

Wearing your avatar, go to Options and click Capture RWX. You will see a message in chat if this is successful.

There will be a new folder in your Worlds installation directory called "capture". This will hold .rwx model captures of all 3 parts of the room. For avatars, you want "capture.rwx". Also in the folder will be all the textures your model was using.

Use Accutrans to convert the model to a .obj or format of your choice.

You are now able to edit your avatar in Blender or a similar program. You will likely have to scale and posistion it by hand.

In blender, you can retexture or rig your avatar with a skeleton to animate it. Here is the tutorial I used to learn how to make a skeleton, and here is me after importing my Worlds avatar into VRChat.

I was also able to use it as a VTuber model:

Tips

If, for some reason, you cannot wear your avatar yourself, you can add a Poseable to the world and set it to your avatar. Now there will be 2 things in the capture, so you will have to delete the parts you don't want in Blender. Stand away from the model you are trying to capture to make this easier.