Art Rules for VR environments?

capone

I'm keen to try and build out a small VR (Oculus) environment but struggling to find any sources that explain the differences between building 3D art for standard screens and VR display.

Also is there yet a clear indication of what works better for VR? Unity or Unreal4?

If anyone could share any knowledge or resources it would be much appreciated!

EarthQuake

I think you'll have to be a bit more specific. What is an example of something you think would work with a regular monitor but not with a VR display? I can't really think of anything personally.

cman2k

Scale Matters; You are much more likely to notice when things aren't built to a real world scale

Efficiency Matters; Care about your FPS and the efficiency of your environments, and don't let your environment be the cause of FPS problems. This will directly impact the end users experience and you could actually contribute to them feeling sick or dizzy because you wanted to spend some performance on something fancy.

Normal maps don't work as well; As VR gets better and better, the 'fake' dimension and lighting of normal maps starts to break down (Source: Valve). This may not matter much now, but in the future we may have to get creative, using tesselation or real geometry more often and not depending on normals to describe larger shapes, only to soften edges and add smaller details. (Another way to say this might be: Bad normal maps will be a lot more obviously bad, so get better at making good normal maps)

Consider vertigo and perspective more; Really good VR will more and more make you feel like you are actually in a place. Large spaces, extremely tall objects, these can start to feel a lot more 'surreal' (and sometimes fake in that sense) than they normally would. You could use that to your advantage, or if you are trying to go for something realistic it could work against you. You could also make your players sick or dizzy by putting them somewhere up very high or moving them around a lot, or moving things around them a lot. Just be conscious of these types of things.


These are my impressions, though I'm no expert. I have talked with Valve about it and experienced their VR Demo though. My impressions write-up is here; http://cmonteroart.blogspot.com/2014/01/i-was-lucky-enough-to-not-only-attend.html

[Deleted User]

With Oculus Rift - I’ve gotten dizzy within 30 seconds of my first try while standing.

Have you tried DK2? Did you had the same feeling with it?

cman2k

I haven't had a chance to try DK2, unfortunately.

monster

At Playful we are building a VR game with Oculus. Before we ended up with our current art style we tried a slew of different art styles. I've developed on DK1, HDKit, Chrystal Cove and DK2 ( and others )

The biggest challenges are mipping and aliasing. The screen is just inches from your eyes and each camera alias and mips slightly differently. This causes a lot of discomfort. You also lose a lot of resolution with the camera shader used to send a distorted image through the lens.

(Anti-Alias is the smoothing of polygonal edges. Mipmapping is the smoothing of textures as the angle / distance increase from the render camera.)

These are the rules we came up with so far.

• Use Chromatic Aberration to correct color bleeding from the lenses.
• Don't use high frequency detail or noise in textures. Even with mip mapping enabled it just turns into swimming pixels.
• 3D geometry "feels" way better than normal maps.
• Specularity instantly give a lot of interest in VR.
• We used a lot of angular and organic shapes because vertical and horizontal lines would align to the screen pixels and alias very badly.
• We rendered the final image at 2592x1458 then down scaled to 1920x1080 to get better anti-aliasing.
• In Unity we used the 8x Multi-Sampling. (Along with the upscaling.)
• Skyboxes require a special shader to display the same on both eyes/cameras.
• We are working on a shader that fades out texture detail at a distance to prevent mipping / swimming textures.
• You need to maintain 76 FPS for low persistence to activate on DK2. This is a challenge because everything is rendered twice, once for each eye.

I'm sure I'm forgetting lots of stuff right now. If I remember anything pertinent I'll update.

cman2k

Nice, thanks for the info dude. Very interesting!

Steppenwolf

Thanks for the insight monster. I'm contemplating to make a night club scene for VR and looking at refs i thought it might be a bit too archviz for my taste and wondered if i shouldn't do something else instead.
But after what you write about noisy textures, specularity and geometry the idea actualy seems perfect to me now.

capone

Yeah there is some fantastic theory here, just what I was after. I was curious why there are no demos with incredible normal mapping etc but I guess we're just not there yet with VR yet? So far the 20 or so DK2 demos are all very simplistic. I was intending on doing a high end small area, with zbrushed assets etc but that's probably not going to make for a great user experience.

Eric Chadwick

Awesome post, monster! Wish the wiki wasn't in flux, this would be a realllly good addition.

[Deleted User]

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Neoekamp

Never had a chance to see anything with Oculus, but how do dark areas hold up in 3d? Say, something like Outlast or Amnesia?

monster

I think dark environments like Outlast or Amnesia would work really well. Especially if you were to limit the render distance. A problem with bright and colorful environments is that you can start seeing individual pixels on the screen. We call it the screen door effect. I imagine they are working to try to fix this for the final hardware, but we can only work with what we have.

ZacD

Nvidia is coming out with a VR headset that supposedly takes care of the screen door effect, and improves resolution and frame-rate.

undin

Screen door effect is awful on mobile VR , I imagine it will give a reason to push mobile screen resolutions even further (which before was ridiculous, but makes sense now I sopose)

Bletzkarn

Unity and Unreal seem to have similar VR capabalities so one is not really better than the other.

There are other best practices, no camera movement, no forced movement and make UI physically floating items in space.

TheGabmeister

Just wanted to add my two cents. It's already been mentioned that normal maps are less effective in VR. For the work I'm doing at the moment, I add more bevels to edges, use Face Weighted Normals , and use tiling materials as much as I can. This way, you can get those nice and proper looking bevels on large scale hard-surface objects. It doesn't work in all situations though, and the Decal technique from Star Citizen doesn't work on Forward Rendering. But on several cases, looks good enough.