Unreal Open Day 2017 Designing Robo Recall

Unreal Open Day 2017
Nick Donaldson
Lead Designer-VR, Epic Games
Designing Robo Recall

Arcade shooter
Oculus Touch
Free!!!
Robo Recall

• Game Pillars
• Teleportation
• Interactions
• Enemies
• HUD
We’ll cover…

• Demo for Oculus Connect
• Made in 10 weeks
• Proved many ideas
• Pre-Pre-Production

Design Pillars
Deciding what our game is.

Design Pillars
• Decide what our game is
• Decide what our game is NOT
• A filter for ideas

Neo - Be The One

Neo - Be The One
• You are the world’s biggest
badass.
• Keanu Reeves simulator

Feels like an arcade game

• A great framework to express:
• Points, multiplier, score, etc.
• Music
• Visuals
• Playful Tone

• What DON’T we have to do?
• Worry too much about story
• Take ourselves too seriously

Unique to Device

Unique to Device
• Challenge standard conventions
• Look for opportunities to take
advantage of the hardware
• How can we make a game that
would ONLY work in VR?

Grounded feels good

20 minute macro loop

20 minute macro loop
• How long can people play our
game?
• “20 minutes” was a guess
• We tuned our mission
length as we tested

Pillars
• Our pillars shaped the direction of our game
• Allowed us to make concise choices
• Prevented second guessing

Teleportation
Why and how we did it.

Locomotion
“Traditional” locomotion
• Uses sticks (or track pad) to move
• Eg. Onward
• Many people get sim sickness

Locomotion
Cockpit Games
• Racing games
• Space shooters etc.
• Eg. Eve Valkyrie

Locomotion
Novel locomotion
• Climbing with hands
• Leaning, swinging arms etc.
• Wacky hardware

Locomotion
Teleportation
• Comfortable!
• We built our fantasy around this
• Empowers the player
• Aligns with our pillars

Teleportation
Bullet Train
• Hold down button
• Point at pre-defined teleport
locations
• Release to teleport

Teleportation
Fundamental limitation:
Oculus touch only has front facing
tracking (by default)
• In Bullet Train we spawned
enemies in front of the player
• All teleport locations are on
outside of play space

Teleportation
Robo Recall
• For Robo Recall, we wanted more
freedom
• Wanted to teleport ANYWHERE!
• Still need to face forwards;
towards sensors

First Prototype

First Prototype
• Laser pointer position ai'ming
• Use hand roll for arrow direction

First Prototype - Issues
• Allows REALLY long teleports
• At low angles, small hand movements move the
end point by many meters!
• Controlling direction with hand roll is unintuitive

Second Prototype

Second Prototype
• Use joystick for arrow instead
• worked very well!
• Still didn’t solve the other issues

Then we saw…

Budget Cuts

Problems solved!
• Natural limit on teleport length
• Easy manipulation of end location
• Everybody understands parabolic arcs

Let’s steal it.

Bonus:
We added a new blueprint function:
Predict projectile path.
•Traces along a parabolic arc at a
specified simulation frequency.
•Outputs path positions and hit
information

So now we’re done, right?
Not quite…

Which way should the player be facing on teleport?
The most intuitive: The same direction as the
teleporter arrow
Front Facing Tracking

PROBLEM:
People quickly turn away from
the sensors

Our Solution:
To use the directional arrow as
the “Tracking forward” direction.

• Less intuitive =(
• Forces players to always be turning
back towards the sensors!
• Seemed like the correct compromise
• A short term problem

Front Facing Circle

Turn Around Text

VR has changed

Interaction
DK1
So futuristic!

A few Oculus prototypes later…

Crescent Bay Prototype (aka. Final spec)
• High resolution display
• Positional Tracking
• Built in headphones

Showdown Demo

Showdown Demo
“Wow! ...but I wish I could hit those
little rocks out of the way!”

Interaction
Grabbing, Reloading, Throwing

Grabbing
Basic Interactions
• Talked about this in Bullet
Train Talk
• Robo Recall uses the same
system

Grabbing
•Meeting player expectations is important.
• If player expects an interaction that doesn’t pay off….

Grabbing
Bullet Train had very narrow scope
•Grab guns and bullets
•Hand-holds on train
•Things highlight when you could grab them

Grabbing
Robo Recall is much more complex
•Grab enemies
•Grab their limbs while held
•Grab many other objects

I needed a visual language for things
that can be grabbed.

The Last of Us

Grabbing
•Circles appear when in range to grab
•Expand when in “hover state”
•Can be grabbed when expanded

Grabbing
•Gave us consistent visual
language
•Players had less frustration

Reloading
…or choosing not to.

Reloading
• Didn’t have time to make
reloading for Bullet Train
• Wanted something really cool.

Reloading
•Reloading wasn’t much fun in other
VR shooters I played.
•Surely I could do it better!

•It was time to use our Pillars
•WWND?
•What Would Neo Do?
Reloading

Well… that’s easier

Reloading
More fun to throw anyway!
•Planted the seed for this in Bullet Train
•What can I do to make this a real part of our
game?

Reloading
•Slomo gun-bouncing
•Automatic reloading
•Slomo during teleport

Reloading
So how do we get new guns??
•Teleporting!
•We used our theme to explain that we
“teleport you new guns”

Holsters
Getting new guns

Built a prototype, quickly found a problem
• Your hips aren’t tracked
• Can we infer your hip position from your head
and hands?
• Not really… Next best thing is head Yaw

That’s problematic
• Players looked down,
tried to look at a gun
• Gun would try to align
to head
• Gimble lock issues

Solution:
• Lerp between yaw based on head
“forward vector” and head “Up vector”

Using Holsters:
• Originally used the standard
grab system
• Worked most of the time
• not good enough!
• Holster failure sucks!

• Had to be very generous
with grabbing holsters
• Used a “quadrant” grab
system

Pressed
Grab
No other
object
highlighted?
Close
enough?
GUNS!

Two Handed Weapons
...Are hard!

• Had a shotgun in Bullet Train
• 75% of players didn’t figure it out
• Lack of rigid physical object causes
hands to drift apart

Throwing
…all the things.

• Not quite the same in VR as
it is in real life (hopefully).
• Results are rarely what
player expects
• We need to help players out:
Aim assist
Throwing

• Built first version in Bullet train
• Find who’s closest to center of view cone
Throwing

• Decent, but not a great metric for where you’re
aiming.
• Would sometimes “steal” the thrown object from
your hand.
• Needed a slightly different approach
Throwing

Bullet Train:
• Based on trying to interpret your intentions
• Needs eye tracking to be done well.
Robo Recall:
• Assumes that your actions are the best indication
of your intent. Just make your throw better!

Instead of view direction, we use hand
velocity instead
Throwing

Needed 2 separate approaches
1. Straight line throw (no gravity)
• Bullets
2. Ballistic throw (with gravity)
• Everything else
Throwing

Straight Line Throw

Throw Target Component

Use velocity to predict ahead

• Assist strength based on the
angle between the input
velocity direction and the
direction to the target.
Straight Line

Straight Line
• The closer you were to hitting,
the stronger the effect.
• Allows natural player feedback
• Players learn to adjust quickly

Straight Line
• In practice, people tend to miss high or low
• We do the strength calculation separately for
the horizontal (XY) and vertical (Z) axes.

Projectile Throw
First pass:
• Calculate intersection
point between projectile
path and horizontal plane.
• Works quite well!

Projectile Throw
First pass:
• But totally fails on
“hard throw” cases.

Projectile Throw
Second Pass:
• Also calculate intersection
with plane that faces
directly towards the throw
location.

Projectile Throw
Second Pass:
• Calculate ”assist strength”
for both
• Use the maximum

Enemies
Filtered heavily through
our design pillars

1. You are…

1. You are Neo

1. You are Neo
• Instead of just being a challenge, I want to be
able to use each enemy as a weapon.
• Empower the player

2. Unique to device
• Touchable
• Grabbable
• Physical

The Biped
Default Enemy

We wanted to beat the crap out of
a robot.

Biped
• Our core enemy type
• We wanted to tear off the arm
and use it as a weapon
• Originally, his arm was going to
be an actual weapon

Biped
• Lots of iteration on how to interact
with them
• VR interactions are very different
than a regular game

Biped
• Explicit context sensitive actions
• On button press it performs an
action, or switches states.

Biped
• In VR, these actions are not pre-canned
animations.
• The player needs to perform these actions!
• There is a lot more room for failure cases

Failure Case:
• Originally, bipeds could only be grabbed when
the player teleported directly to them.
• Players expected to be able to grab them all the
time.
• Caused frustration when expectations not met.

More Fail:
• When you grabbed an enemy, we enabled
physics, and allow you to punch them.
• Lots of fun!
• People wanted to do it without first grabbing the
enemies.

• I had planned these states
so carefully!
• Can’t argue with the players
More Fail:

Biped
• We made every enemy within reaching distance
of the player fully simulate physics
• We made a new “Physical animation” system
• Now available in UE4
• Uses physics to try to match animations

Biped
• We spent a lot of time making sure that
every action a player wanted to perform
would function correctly.
• Rich, robust interactions are very
rewarding for the player

Biped
All that to say;
• Biped can be interacted with in many
different, complex ways as a weapon
against other enemies

Crawler
Boom spider

…because giant robot spiders in
VR is fun!

Crawler
• We first added these to exploit the “presence” of
VR.
• People get strong reactions from spiders.

Crawler
• We refined the idea of using all enemies as
weapons
• Explode them to destroy other bots
• Throw or hit like explosive baseball

Failed prototypes
• Originally crawler would have a laser and be held
like a gun.
• Conflicted with “up and personal” idea
• This idea turned into drone
• Instead of just exploding, crawler was “hijacked”
and would heat-seak an enemy.
• Was too slow, and lacked feedback

Drone
Flying gun

I wanted a robot that was also a gun.

Drone
• Based on failed Crawler prototype
• Modelled out of borrowed geometry from crawler
• One of the few enemies who’s weapon you can’t
deflect.
• Forces you to teleport or move your body

Fastbot
Run and teleport

We wanted an enemy that was fast
and could teleport, like you.

Fastbot
• I built a prototype where she teleports when shot.
• Worked very well!
• Positional audio is great.
• You can tell where she’s teleporting to without
even looking!

Fastbot
Other than teleporting, how is
she going to attack you?
• This took us a long time to
figure out!

Fastbot
This needed to serve 2 functions:
1. What can she do to you that is interesting?
2. More importantly: How can the player use this
against other enemies?

Inspiration:

Fastbot
The Whip:
1. Stops you from teleporting if she
hits you
2. Can be used against other
enemies as a big physics arm

FlyingBot
Metal angry bird

I wanted a robot that you could turn
into an angry bird.

This needed to serve 2 functions:

FlyingBot
I build a prototype of this “angry birds” functionality
quite early
• Moving around such a big creature with one hand is
difficult
• Had to iterate on this a few times
• Still a little rough around the edges

FlyingBot
• We had to find the fun for the rest of his behavior
much later in development.
• AI came online very late
• Experiment to find the fun

BigBot
Big… Robot….

We wanted a robot with a sense of
scale…. BIG!

Bigbot
What if you could hijack him, and be almost
invincible??
• Took the “use against other enemies” to the
extreme.
• Grab and throw enemies like toys

Bigbot
• Prototype the coolest part first
• More risk- We didn’t know if this was going
to work.
• Solve the more traditional parts last
• Less risk

UI and HUD
Displaying information

HUD
In staying with out Arcade game pillar, we had some
information we wanted to convey in-game.
• Score
• Multiplier
• “Scoring Events” or “Trick-shots”

HUD
VR “Best Practices” say to keep as much UI in-
world as possible.
• This is true!
• Scoring events worked perfectly in-world

HUD
But what about persistent information?
…lots of iteration.

HUD
• First tried HUD
• Tried having score on a “wrist watch”
• Someone else tried a HUD
• Tracking space vs. Camera space

HUD
Then tried wrist watch again
• Nobody ever looked at the watch
• Also tried ”Pause” menu on watch
• Awkward angle to interact with

HUD
Then we asked… Do we need a HUD?
• We added current multiplier to
”scoring events”
• Too much information!

HUD
Finally returned to classic HUD
• Stuck to your face
• Not perfect but..
….actually worked!

HUD
We put this on-screen during gameplay, and
noticed an issue:
Any HUD in the center zone of the screen got
in the way.

HUD
• To draw attention to information, whenever
there’s an update we animate size and color.
• We animate “Multiplier chips” moving towards the
HUD element

Whole project on Epic Games Launcher!

Thank you!
Robo Recall Team
Epic Games China

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Unreal Open Day 2017 Designing Robo Recall

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