I am in the process of learning UE4 to port my game (The Stacks) to it.
There are a lot of oddities to configuration that needed adjusted. My hope is that this helps others starting to use UE4 for Oculus Rift development:
#1. The scale of default door and frame are wrong. The door is 200cm tall. That is 6.56 feet. Doors in my house are 6.8 feet. This means you need it to be 208cm. That is a scaling factor of 1.04. That doesn't mean I'm going to use their door frame but if you are using that to gauge if scale is correct in the game, 3 inches is a big deal. I felt like my head was scraping the top of the door.
#2. I'm 5 foot 8. The default height for a player is much taller. To adjust this go to the MyCharacter blueprint, click default and search for height. you want to set "capsule half height" to 1/2 your height in centimeters. My height is 172cm/2 = 86.
The next set of adjustments require a post processing volume. You can find it in "All Classes" if you don't have one. Drag it into your scene. search for unbound detail and check that so it applies to everything.
#3. There is a blur as you approach objects. This is an anti-alias method of temporal and it is super annoying. search the post processing volume for AA Method. Set that to none.
#4. Lens flare has to go. Search for Lens and set the Intensity and BokehSize to 0.
#5. Scenes in the rift get unusually bright. That is auto exposure. Search for exp. I don't know exactly the best settings but I am using min brightness = .5, max brightness = 1, auto exposure = 0.
The other thing that bothered me was the IPD feels different. Up to now I hadn't adjusted it on the DK1. UDK3 felt perfect. I had to adjust it for UE4 to make it not give me a headache.
That is a start I will update this thread when I am deep into development and have sorted through any other unpleasantness.
My initial impression with UE4 versus UDK3 is that it doesn't feel as nice in the Rift. UDK3 felt like Half Life 2 which was very 'crisp'. UE4 feels more 'fuzzy' like Unity. UE4 certainly comes packed with more flexibility but it feels like a step back for Rift support.