How Prey uses a foliage shader to make its aliens look alien

- Lead visual designer Emmanuel Petit, speaking to Rock, Paper, Shotgun about creating the alien enemies of Prey.

The alien opposition players face in Arkane's Prey are well in line, visually, with classic sci-fi horror fare: hazy and black, with lots of goopy black tendrils and eyes shining out from face-like voids..

So how did the designers pull that off, exactly, and what did they do to make the creatures (or Typhon) look and feel alien? That's exactly what Rock, Paper, Shotgun asks after in a newly-published interview with Prey lead  visual designer Emmanuel Petit and lead visual effects artist Jason Timmons, and the pair's anecdotes make for interesting reading.

"The development of those creatures has been really atypical and challenging as those designs were in constant evolution.," said Petit. "As far as visuals there was very little that we could act on; given that those are black and blurry, all of the visual complexity has to be indicated in the silhouette. A good reference as far as I’m concerned is time-lapse photography of people, especially dancers in motion, and in particular the Metamorphosis series by Frederic Fontenoy [NSFW]." 

The pair go on to explain how they tried to make every alien seem like a real creature "that does weird shit" (in the words of project lead and departing studio co-chief Raphael Colantonio) within the limits of the Typhon aesthetic (pitch-black, hazy, no meaningful communication skills.)

Most notably, they rigged the (Cry)engine to apply a slight motion blur to the creatures at all times, even at rest, and slapped them with a vertex deformation shader originally designed to animate foliage.  

"First time we used it for something else than the vegetation foliage was for the Coral, then we carried that feature over to the rest of the Typhon line up," Petit said. "It was a simple way to add something interesting to those creatures."

For more anecdotes from both Petit and Timmons, check out the full interview over on RPS.