Tutorial: Adding Glow
This tutorial will go over adding hero glow to the Rifleman. Basically the same thing can be done to any unit to add glow.
MDL(s) needed: Rifleman (Units\Human\Rifleman\Rifleman.MDX), Keeper of the Grove (Units\NightElf\HeroKeeperOfTheGrove\HeroKeeperOfTheGrove.MDX)

You will need the ObjectId Inserter and Vertex Modifier as well.
  • Getting the glow geoset
    • Glow is nothing more than a number of planes on top of one another. It's simpler to just get it from an existing unit than to make it yourself.
    • First, pick a hero to take the glow from. In for this example, I chose the Keeper of the Grove.
    • Open that hero in the vertex modifier and choose the geoset that contains the glow. You can find which has the glow by unchecking their visibility in the previewer until the glow disappears. In the Keeper's case, it's number three.
    • Go to File->Save Geoset and save as Glow.mdl.
  • Adding the glow bone
    • Every vertex, including those of the glow, needs a bone to follow. Unfortunately, most units do not already have a bone that doesn't move at all, so it has to be added.
    • Because all the bones have to go together, we have to know where (after which ObjectId) to insert the bone. Open the MDL you're adding the glow to in Notepad (or another text editor) and find the ObjectId of the last bone listed. Just search for "Bone" (no quotes) until it runs gets to the last one. It will have a line that says "ObjectId ##,". In the Rifleman's case, the last one is twenty-nine.
    • Open the ObjectId Inserter. Set the base file to the Rifleman, the "Insert after" field to 29 (or whatever your last bone's ObjectId is), the "Number to insert" field to 1, and the output to something like RiflemanGlow1.mdl. Click "Insert". Room for a new bone in that area will have been made.
    • In a text editor, open RiflemanGlowy1.mdl and find the spot after the last bone and before the last helper. Paste this new bone into it: 
      Bone "Glow" {
	ObjectId 30,
	GeosetId Multiple,
	GeosetAnimId 0,
}
      If you're doing a different MDL, then the ObjectId will be different. Just make it (the ObjectId of the last bone) + 1.
    • Make sure that you can still convert back to MDX at this point. If you can't, check all your steps so far.
  • Attaching the glow
    • Open the Geoset Merger.
    • Set the base file to RiflemanGlowy1.mdl.
    • Set the geoset file to the hero's glow that you exported at the beginning.
    • Set the output file to something like RiflemanGlowy2.mdl.
    • Leave the path blank. Glow is one of the presets.
    • Check the two-sided box.
    • Change the mode to "Additive".
    • Change the bone to "Glow: No parent". It's the one you added.
    • Click "Merge"
    • Test and everything should be working.