Texture Mapping for Unreal VR

[Matt Sugden]

Hi I'm starting to explore Unreal VR development with Quest 2. Typically when I texture a model for Vray I'm mostly using real world mapping box/cylinder/planar etc, multisub objects with maybe 50+ ids and I don't use single unwrapUVs almost ever. 

However it seems that the world of real-time requires huge amounts of optimisation to look good, unwrapping textures, projection mapping for normals etc. However unwrapping a model to texture in photoshop seems painful, scaling materials in photoshop is so cumbersome and it means all the textures are all on one map, so then creating the roughness/reflection maps etc is all in one place. It doesn't seem intuitive or flexible. Am I missing some vital workflow here?

How are arch vis people approaching the use of adding textures?

 

Edited April 22, 2021 by Matt Sugden

[James Vella]

You can use your standard realworld mapping technique for uv channel 0. In unreal you just tile the texture by x amount in the material settings. 

The only difference really is making sure uv channel 1 (lightmap) is unwrapped and non overlapping - which can be done automatically or manually unwrap in 3dsmax (channel 2). Just keep in mind uv channel 0 is uv channel 1 in 3dsmax, and so on.

 

[Jose Gabriel Ruiz Gonzalvez]

Hi, u can try to use triplanar mapping.

 

But if u want to develop for Quest2 ... u need to do the optimization.

 

[Francisco Penaloza]

Well the answer is not simple really, and there are many ways to approach it.   Besides one thing is real time engines, other is VR and mobile VR such Quest 2.

First needless to say, objects with 50+ id I don't think is a good idea no matter what.

But alas, as mentioned by others, first you need to focus on your final output. On this case mobile VR headset, with this there will be limitations, these limitations are well explained on Unreal Helps for Mobile VR. For example, AO, reflections, Real-time lighting, they all get compromised, because of that you will have to Bake the lighting, and yes you will have to optimize the numbers of textures and also the amount of them, There is something called Draw call, that in lay therms,  is the speed or time that one asset is loaded in to the video memory. Each object, texture, shader etc has to be loaded in to memory, the faster this happens the better FPS you will get, for VR this should be Minimum 90 FPS, Oculus said they can get a long with 70 FPS. In my experience at 70FPS you will get blurriness and make people uneasy or dizzy.

Regarding textures in Photoshop, I guess you refers to some game assets that have many textures on a single image. like a person jacket, pants and shirt everything unwrapped on a single texture. Yes that would be the optimum way to do it, but for Architecture this is not practical at all.  Thankfully Datasmith does most of the heavy work for you. In theory you can keep your materials and shaders as they are in your 3D app and then use Datasmith to export to Unreal, inside unreal you setup your project to be Mobile VR and then you'll see in real-time how your scene will look and perform.  The latest Unreal has a GPU light mass baker, that is way faster than the traditional CPU Lightmass, this really help with large scenes, but again in your Mobile device this should be limited, don't think that you can put a whole building tower with all furniture into a VR experience, you will have to subdivide, delete what is not in view and maybe even separate your working areas on levels, just like games, for example if it is a house, you can have one level with the Living room and Kitchen, the other level with the master bedroom, and so on.

The Unreal help docs touch many of this, the info sometimes gets very ambiguous, the unreal forum is helpless at best, but you can fing decent info from time to time. I would recommend You-tube or pay some Unreal courses online.  Even in this forum is hard to get straight answers for some reason.  I am not an expert, my learning is try and error but I can't promise any tutorials because my workload is too big, I need time for decompress too ?

Quick question I would be happy to answer thought.

Best luck.