Mount & Blade II: Bannerlord — Accuracy Reins Supreme
Mount & Blade II: Bannerlord is a medieval action role-playing game that has been in development for the better part of a decade. The long awaited sequel to Mount & Blade: Warband is being developed by Turkish studio TaleWorlds Entertainment, and a conrete release date has not yet been announced.
Their most recent update goes into detail about changes made to the behavior of reins: Mounted combat is one of the game’s focal points, claims the post. The previous implementation had reins hanging motionless and stiff over the mount’s neck, which the team was not happy with.
The post does not go into too much technical detail, but the developers explain how the reins are a bit of a special case compared to most applications of cloth physics because they are fixed in two places: at the bit and in the hand.
Now, in Taleworlds, whenever we run into a problem, we do one of two things: We either lock ourselves into the meeting room with a jug of coffee and brainstorm until we find a solution, or we skip that step and go and use inverse kinematics. In this case, we employed the second approach. Using inverse kinematics we made sure that the rider’s hand would stay more or less in a position close to the horse’s neck. Combined with some small fixes to animations, this worked great and we were able to get the look and feel we were aiming for.
Inverse Kinematics refers to the process of determining the other behaviour of digital elements by starting at the end of a chain of things that influence each other, rather than at the beginning. In this case, the position of reins and player hands determines the positions and angles of elbow and arm, rather than the other way around.
The post includes two gifs of how the riding will look in the game:
The trot and canter animation in the first gif looks very promising in my opinion. The horse’s motion looks solid and the movement has some real weight to it. The physics of mane and tail are nice and the newly improved rein behavior looks better than most implementations I’ve seen. Reins in games have a tendency to look either entirely stiff or way too floppy, and Mount & Blade seems to have found a good solution.
That being said, the second gif is unfortunately a prime case of “how did nobody see this?” when it comes to horse anatomy.
In this rearing animation, the movement of body and legs are completely fine in my opinion, but the angle of the horse’s head is painfully wrong for anyone who’s familiar with horses and their anatomy. The digital mount’s chin bends back almost enough to touch the base of its neck.
While it’s unfortunately true that some riders overbend their horse at the poll (i.e. where the head meets the neck), what we see here is not just “possible but unhealthy” but physically incorrect: the horse’s jaw basically disappears into its neck in the animation.
TaleWorlds obviously cares a lot about the detail and accuracy of their medieval mounted combat and are putting a lot of work into it. Compared to using inverse kinematics and cloth physics to ensure proper rein behavior, tweaking the exact head angle in this rearing animation should be relatively trivial.
With no release date announced even 8 years after the game’s initial reveal, let’s hope Mount & Blade II: Bannerlord finds the time to make sure that their titular mounts stand up to the obvservations of equestrians in the future. The devs’ commitment to getting reins right is definitely a good start.
Read the full dev post here.
Mount & Blade II: Bannerlord is announced for PC and does not yet have a release date.