If you don't want to read my tutorial please look here at a more professional and in-depth explanation to this type of stuff:
Be a Modder: Doctoring of Medieval 2 units. http://www.twcenter.net/forums/showthread.php?t=412456
First, download Mesh 2 ms3d from here: http://www.twcenter.net/forums/downloads.php?do=file&id=1276
Second, download Milkshape 3D version 1.8.4 here: http://chumbalum.swissquake.ch/ms3d/download.html
These 2 are necessary to convert the model into a file in which you can edit it. Unpack them somewhere.
1.Grab the mesh files of the boyars, you can know where they are from opening up the battle_models.modelb file in the unit_models folder in SS's data folder and looking up the "boyars" entry. Place the mesh files somewhere where you can work on them.
2.Start up the Mesh 2 ms3d exe and you'll see a green window come up, on the left hand corner go to file, convert, mesh to ms3d. Find wherever you placed the boyar's mesh file and once you see the white model of the boyar in the green window save it somewhere.
3.Exit out of Mesh 2 ms3d and start Milkshape 3D. Once the window pops up, go to the left hand corner and under the file tab click open and find your boyar's ms3d file. Once the model appears in the windows of the program go to the Groups tab on the right and find the lances, usually you can double click on each item which highlights what they are on the model's body but since it's a lance it should be easy to find.
4.Once you find the lance or lances, click on the one or ones you want to remove and press delete (not the delete on your keyboard but the delete button under the list inside the milkshape program).
5.Once the desired items you wanted to remove are gone, find the swords or secondary weapons of the boyars. Do this for each of them: Click on one to highlight it on the list and then look below the list for the button called "comment" and click that. A small window will pop up like this (e.g.):
secondaryactive0
sword primary_03
0
See that first line where it says "secondaryactive0"? Change it to primaryactive0 instead. Do this to each of their secondary weapons so that you can see them ingame once you're done.
6.Once done, save the ms3d file and close out of milkshape. Start up mesh to ms3d again and this time under file, convert, you click ms3d to mesh instead. Find the boyar ms3d file you just edited and then save it somewhere.
7. Now comes the text editing. Close out of mesh to ms3d if you haven't and now since you're trying to replace a model of a unit, if you want you can just place the file where the dismounted boyars are located and rename the boyar file you had edited to the name of the dismounted boyar mesh file. Rename it after the dismounted boyar mesh that had the ending like this "lod0.mesh".
dismounted_boyars_lod0.mesh
dismounted_boyars_lod1.mesh
dismounted_boyars_lod2.mesh
dismounted_boyars_lod3.mesh
8. Open up the battle_models.modelb file again, find where the dismounted_boyars entry is. Now this part is if you used only one boyar mesh file to edit, which you most likely have. In the dismounted_boyars entry you'll see this:
Delete these words in red:
Change the "1 4" you see at the top to a "1 1", without quotations, and the "121" at the end of the first line you didn't delete to be "6400".
9. Now find the entry where the Boyars are located which look like this:
And copy the kievan_rus and russia lines in red to replace the kievan_rus and russia line over at the dismounted_boyar entry. Well you can actually do it with any of the entries here even if they're not in red since they all use the same texture file. Your dismounted_boyars entry should now look like this:
The changes are in RED
It should work now. Sorry if my attempted tutorial was confusing or doesn't work for you. I'm not good at creating modding tutorials. However please look at this tutorial here for a more in-depth explanation to these things:
Be a Modder: Doctoring of Medieval 2 units. http://www.twcenter.net/forums/showthread.php?t=412456