Immersion is the holy grail in Virtual Reality. In terms of differentiation from a traditional videogame the sensation of being there is from far the most rewarding feature of virtual reality.  But it is also the most fragile one. Make a mistake and the illusion breaks in pieces.

As written dozens of times before, Virtual Reality tricks our mind to levels never seen before. The sense of depth is so real that it’s being used on medical treatments like heights fear and when this kind of immersion is achieved we are talking about presence.

Some time ago I’ve been in a talk in Granada Gaming about presence. There, Luca Mefisto (VR developer and co-organizer of VR Manchester), told us about what is and what not a real VR experience. Lots of VR content like 360 videos are great, but are far from the “R” of VR.
To be a “reality” you need to forget about the real world. You know, that moment when you take off the headset and you realize that it’s dark outside and you started to play just after having lunch, but you tough you played only 1h.

The main problem with presence is coherence. We don’t need to mirror every aspect of the real world, and even more, we don’t need photorealistic graphics to have an authentic environment. Even a cartoonish world can trick our mind to that point that we feel cartoonish  too and thus, create presence. But it’s important to be loyal to the world’s rules or its coherence will break and then, presence too.

Today we want to talk about scale, one of the most common problems with coherence. For example, if you can find something like a coffee cup in the game, you will need to ensure that it’s correctly scaled in VR, because if it’s too small or too big, coherence will be compromised and the illusion of presence disappears because something is different from what you expect from the world.

We are developing Unforgiven VR, a multiplayer game about dueling in the wild west. We expect to be on Early Access soon with a simple you-and-me-duel-now mechanic and we will be expanding options like different weapons, character customization and more game modes.

We developed a prototype and it was really fun, then we started to model the first character and once we replaced the dummy with a real person model scale turned to be a nightmare.

In the game we track your head and hands and the character will move accordingly using with Inverse Kinematics. The same is applicable to your opponent in front of you. It will be ideal if every person out there has the same height, but sadly it’s not true and… what happens if you are 4 feet tall and the character is 6?

Remember, we have two problems here. First of all, the scale of the world for the viewer, and in second place, the size of the character in front of you. We played with three possible solutions.

1- Scale the character to the player's height

That was the obvious option, it will maintain the coherence for the player who is playing because all the world around him will be scaled to its height and then, the presence will be intact.

But what happens to the other player? Imagine you’re facing a child around 4 feet. The characters are all adults with a similar height around 6 feet, then, if we scale it down to 4, it’s a very strange vision, like facing a toy. And it also happens if you have a 7 feet person, then it seems you are dueling a Moria’s troll.

This is a problem specially from the competitive perspective. A short person will have advantage because its size will make it harder to be hit.

2- The character mimics the player movements

Ok, do not touch the character size. Just take the movements of the VIVE and assign to the skeleton of the model.

Yes, we fixed the above problem, you can see a normal person, and it moves correctly. Great! Isn’t it?
No, I’m sorry. It’s a dueling game, it’s about firing from your hip, fast enough to hit the other player before he can aim. Then, what position do we take into consideration to fire the bullet? The player’s one and the avatar’s are not exactly the same, mainly due to the height difference we talked about.

Too many problems from a gameplay perspective for a competitive game.

3- Scale the player

Wait, wait, you can’t go to the player home and give him a hyper-duper-accelerated growth treatment.

With the HTC Vive we have and special object called CameraRig. It’s the responsible to get the tracking data and reproduce the head and hands movements. It’s a 3D object that you can add to the virtual world and like the other ones, it can be moved and scaled.

And that’s what we do, we scale the players size to the character’s one. This approach has the benefit that the character and the player moves are nearly identical and then, we can use the data to be sure that where the player aims is where the hand is and the bullet will go in the correct trajectory.

The bad part is the coherence. It’s a little bit shocking for a player to play the game if his height is too different from the character’s. For the taller ones it’s like the world shrinks, and vice versa for the short ones.

If it’s the case you’ll need some time to familiarize with the world. It’s not perfect, but as we’ve seen it’s a very common issue with the games that shows parts of the body. For example in the new Batman: Arkham VR you can see your hands and for me, they were too small.

As stated before, being Unforgiven VR a competitive game, we are sure that this is the best approach to ensure players a fair duel in the sun.