how do you enable symmetry, so that if you edit vertices on one side of the mesh, the vertices on the other side are mirrored to reflect those changes
Create half your mesh, then use the Mirror Modifier to create the other half.
Right, see http://wiki.blender.org/index.php/Manual/Mirror_Modifier for more details.
Yeah, i think so. heheh.
ok I had a complete character rigged and vertex groups created, but wanted to sync the left and right sides of the mesh, so I deleted half the mesh and am using the mirror modifier
but now I am left with vertex groups for both sides of the mesh eg UpArm_L and UpArm_R etc.
UpArm_L now controlls both sides of the mesh- isnt that going to cause problems with the bones- I cant modify the right side of the mesh anymore because its just a mirror modifier
Once you have finalized the model…its better to apply the mirror modifier so that you are left with one single mesh before you start skinning.
First, apply the mirror modifier if you haven’t done so already. Next, make sure you have deselected all vertexes in edit mode, and on your vertex group pop-up menu select UpArm_L and press Select. Manually deselect all the vertexes on the left side, then create a new group and call it UpArm_R, and press Assign. Without selecting or deselecting anything, go back the to group UpArm_L and press Remove. This should fix the mesh for the UpArm_L/UpArm_R bones. For the rest of the armiture, repeat the process.