To Join or Not?
Once the avatar is in place some tutorials recommend joining the parts of the avatar together into one part. Joining them is not necessary. But, it can simply your life. Gaia joins her’s. Ashasekayi and I make one joined and leave another copy in parts.
Gaia explains the joining process with a neat added step I like. To keep track of the parts Gaia marks the edges of the parts as seams. It is easy and seams are handy things so, let’s do it.
Clear all selections (press A). Select the lower body part (right-click). Enter Edit Mode (press Tab). Press A to clear selections. Press 1 or 3 to orient the view, side or front works best. Press B and drag to select the top row of vertices. (See image) In the left column in Mesh Tools is a Mark Seam button, click it. Or press Ctrl-E and select Mark Seam. Press Tab to exit Edit Mode.
Right-click the torso: to select it. Then press Tab. Select the bottom row of torso vertices and mark them as a seam. Repeat this process at the neck. Then repeat it for the head. You should have some seams like I show in the image. All the vertices making a seam should be in a single ring or loop on the edge of the part.
Press Tab to change the 3D View to Edit Mode then press A once or twice to select all the vertices in the current part. Again on the left in Mesh Tools find and click Remove Doubles. This cleans up the model.
Note: A ‘double’ is two or more vertex points occupying the same 3D position. There are legitimate reasons for there being doubles in a mesh. But, often doubles are left over vertices or mistakes we didn’t notice while modeling. For our purposes now there should be no doubles.
Now we are prepared to join the parts into a single mesh part. Later we will deal with the actual joining. First we want to weight the individual parts. Then we’ll come back to joining. I’m doing the weighting now because it is a computer speed thing. Weighting can take 5 to 10 minutes depending on the computer.
Attach the Rig – Parenting
To start the weighting process we need the armature or skeleton and the mesh model connected. In future work you will need to connect clothes to the armature the same way. So let’s get that done.
You should have your avatar and the armature on the X-Y zero location. In Domino’s file the armature is in the correct location. Provided your 3D cursor was at 0,0,0 when you imported your avatar mesh, it will be in the correct location too.
To check: in Object Mode select the head. You may need to press ‘N’ to see the Transform information. The N-key opens and closes a panel in the right of the 3D window. At the top of the panel is the label Transform and a location read out. It should read 0,0,0. If not you will need to reposition your avatar. Otherwise, you will have problems with future rigging.
To set the objects to the ZERO position, you can simply type of the numbers in the panel and press TAB or ENTER. The object will move.
With the head selected press Shift and right-click the armature. Press Ctrl-P or via the menu at the bottom of the window click Object->Parent->Set->Armature Deform. This will set the avatar mesh to move as the armature moves. Repeat this process for the torso and legs.
You can check to see that the parenting worked. Checking will also help you understand what weighting does when we get to it.
In the bottom menu set your pivot point to Individual Origins. Change from Object Mode to Pose Mode. Right-click a bone: to select one. I chose the lower leg. Press R to enter Rotate and move the mouse. You should see the mesh move with the bone. It is NOT going to be the nice joint movement you see your avatar make in world. In fact both legs are going to move when I move only one leg bone. The whole mesh is going to deform because we have yet to add the vertex weighting, so the system can know how much and which vertices to move with the bone. Without weighting, it moves everything.
Doing the Weighting
As you make clothes you will need to weight them too. So, weighting an avatar is a good example of how to do future clothes weighting. In some tutorials this weighting is also called vertex painting. That can be confusing because there are multiple types of vertex painting that do different things. A more accurate phrasing would be vertex weight painting.
Size is important in the next steps. You need to scale whatever you are working on so that it is as close to the size of the original avatar as possible. The Bone Weight Copy works best when things are close to the same size. So, a t-shirt should fit the base avatar as well as possible for this step. You can rescale to the size you want after the weighting is complete.
Look in the Transform panel (N-Key) and check the scale of the item you are about to weight. All the scale values should be 1.000 (one) and rotations 0.0 for your mesh BEFORE you scale it up or down to fit the base avatar. Press Ctrl-A to apply any rotation or scaling to set the vales to zero and one. Now you can scale your mesh to fit the base avatar. After it is weighted you can manually set the scale values to one to restore it to your original size.