I don’t see many tutorials about rigging mesh for OpenSim. But, Hypergrid Business has a new one. See: Quick mesh rigging how-to. Of course the procedure will work for Second Life too. But, this is for ‘rigged’ mesh only, not fitted mesh.
While they use the Machinimatrix base avatar, you do not need AvaStar. However, not having AvaStar means using the parts of the model included for working with fitted mesh is awkward and not at all intuitive.
I haven’t played in OpenSim since OSGrid crashed. So, I am not sure whether or not we can use fitted mesh in OpenSim. So, this tutorial is more than adequate for most of those making clothes in OpenSim.
notice you tutorial on rigged mesh from http://www.hypergridbusiness.com/2015/06/quick-mesh-rigging-how-to/
I have done a tutorial about a year ago now on rigged mesh avatar on opensim ( HG opensim location search in map for 3d.gimisa.ca:9000 in gimisa5). You will find in that region a import mesh house inside which there is a group of tutorial on importing mesh to SL/OpenSim. The objects I am using for demo are freely available mesh 3d model from the nasa at: http://www.nasa.gov/multimedia/3d_resources/#.VZu7cvl_NBc .
I use the shuttle craft to present importing large model, and the astronaut to show how to rig and import avatar. I hope that it might be useful to you in opensim / SL .
hope it helps
Thanks for the information 🙂