False Perspective

A video game trick, to provide a stronger perception of speed

1993- We are building a 3DO version of Road Rash internally at Electronic Arts. The team has done a great job rebuilding the success of the Sega Genesis game in a 3D scene on the 3DO player:

However, as we are just a few weeks from finishing, I am frustrated that the game does not “feel” as fast as the genesis version, or as fast as arcade games like Out Run:

However, the design constrains seems to force us to the speed we are using:
– the object on the horizon needs to appear a specific fraction of a second before it could collide with your bike.
– the distance of the horizon is fixed for performance reason.

As I am thinking about this, I do some experimenting about what feels fast and what feels slow.
Quickly I figure out that the perception of speed comes from the large objects near the scree, and not from the small objects which are near the horizon.

So, maybe we can slow down the object when they are near the horizon, and accelerate them when they are big…

But that’s control by the law of perspective. which says that the size of something is proportional to the inverse of the distance.

Who cares?

Since we are using a look up table to calculate 1/z anyway, maybe we can just cheat…

Here is the curve we actually used. and the test we did to measure the effect:

In this GIF animation, the objects start at the same time at the horizon, and they cross the red line at the same time, but the yellow one give the perception of going faster…

And that’s what we ship in Road Rash 3DO in early 1994…

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