Here is a simple way to make many creatures mounted, without needing a combined mesh from 3DS Max or even a combined mesh from the game. All you need is Tamchi's MeshView program. Here are the steps:
1. Open the mesh of the creature that you want to be the rider in MeshView. It is recommended to be human-like for the mounted animation to work properly. Inside the mesh, on top of TextData section paste the following:
AttachPoint
{
name = "Mount"
origin = (0.0000000, 0.0000000, 0.0000000)
xAxis = (1.0000000, 0.0000000, 0.0000000)
yAxis = (0.0000000, 1.0000000, 0.0000000)
zAxis = (0.0000000, 0.0000000, 1.0000000)
}
2. Now scroll down in TextData section and at the very bottom paste the following:
CreateEntity
{
attach = "Mount"
entity = "records\creature\monster\saberlion\am_saberlion_21.dbr"
}
Then save the mesh.
The saberlion record link is just an example, you can use some similar creature or any creature that is used as mount in the game - Hyena, Bear, Boar or Saberlion. However I think with this method its quite possible to make a mountable wolf for example. Continue to read and you will see why.
3. Time for the second part. Open the Mesh of the creature you want to be the mount. In the Mesh you will see Bones section. When you open it you will see list of all the creature's bones. It looks like this:
4. Open each Bone separately and add "_MOUNT" after its name. In the end it should look like this:
5. Next, open the TextData section of the mount and in it add "_MOUNT" to each bone reference, in the Attach Points, SkeletonEmmitterBones and RigidBodyDescription:
This is all done for the mesh bones to be able to read the "..._MOUNT" Bones in the Mounted Animation files (which contents the combined Rider + Mount animations). This is all that you need to edit. Save the mesh.
6. Next, place the rider mesh in "Titan Quest Anniversary Edition/Database/Creatures/PC/Male" or "Titan Quest Anniversary Edition/Database/Creatures/PC/Female". I suggest you to start with a human first. Then in "Titan Quest Anniversary Edition/Database/Creatures/Monster/Saberlion" folder place the mount mesh. (or in the hyena folder, if you are using hyena, etc.). It has to be in the same directory where you extracted it, only in Database, not in Resources.
7. Now comes the more tricky part - animation. Animation is really the key for all this to work. In the given example, extract all mounted ANM files from "Titan Quest Anniversary Edition/Database/Monster/Neanderthal/ANM" folder and place them in "Titan Quest Anniversary Edition/Database/Creatures/PC/Male(Female)/ANM" folder.
Rename each from them to character animations (e.g. "neanderthalmounted_spear_idle.anm" to "malepc_idle.anm"). Launch the game. The character will be riding a lion, using mounted animation.