If you are talking about (in the Max skin modifier), selecting vertices by the bone they are currently assigned to then there are a few lines of maxscript that can do this:
--selects the vertices that are influenced by the currently selected bone
s = modpanel.getCurrentObject()
-- if the current modifier selected is a skin modifier, then select the vertices
if iskindof s Skin do
(
skinOps.selectVerticesByBone s
)
You need to have the bone you are interested in selected in the Max skin modifier rollout and Edit Envelopes active with select vertices checked as shown below and then run the script.
I have attached the macroscript version of the script. Unzip the attached, then drag the file SelectVertsbyBone.mcr to a Max viewport to install it (this doesn't actually run the script, just installs it in a Max directory). Then the script will appear under Customize>Customize user preferences where you can put the script on a custom toolbar or hotkey it to actually run it.
The script makes it easy to re-assign vertex skin weights as you are describing and I use it regularly.
If instead you are talking about something different then post back a clarification of your question. Hope it helps.
