I will be taking 3ds Max and Vray lighting workflow as a reference to recreate the same in Unreal Engine 4. Main focus will be on Unreal Engine, just giving reference to 3ds max and Vray settings. (It’s not a 3ds Max and Vray Tutorial)
General Lighting methods prevailing in Arch-Vis industry using 3ds Max and Vray –
- Exteriors (Combinations)
- VraySun + VraySky
- VrayDomelight with HDRI + Directional Light (For simulating sun, if required)
- Artificial Lights as per requirement (mainly in Dusk shots)
- Interiors (Combinations)
- VraySun + VraySky + Vray Skyportals
- VrayDomelight with HDRI
- Artificail lights as per requirement (used as fill lights or sometime required to create a desired mood)
* Artificial lights – Any Vray light (Area, point, IES etc) used as fill light or to create any specific mood.
I will be recreating this workflow concerned with HDRI and Directional light as SUN light for Interiors and Exteriors. It is imperative that we first know how to use HDRI correctly to simulate proper lighting with correct exposure.
In above scenarios (Exterior and Interior) VrayPhysical Camera plays a vital role in simulating DSLR exposure with physically accurate lighting values (Real life light intensity values in Luminance or Radiance).
It is important to know why we use Physical Camera features in any Rendering Engine. In real life, human eye plays a critical role in compensating for difference in light intensities we encounter on daily basis by controlling amount of light entering, through increasing or decreasing iris size.
When it comes to simulating human eye behavior technically, DSLR Cameras come really close to do so with ample amount of control and as we are already using these cameras to take photographs of our surroundings, it is easy if we recreate those settings virtually in our rendering engines also. It’s a well-known fact that to render virtual images/environments, basic knowledge of photography and light behavior plays a critical role.
Reading these articles will certainly help a lot (highly recommended)
When we take photographs with DSLR camera on “Manual mode”, we start to get an idea about the settings concerned to capture “what we are seeing in real time” and “what we are getting as photograph” ( not too bright or too dark). I will not be divulging much into DSLR and Manual settings more, but that does not mean I will leave it here as it is – for all the techno freak guys, reading this material will certainly help (I highly recommend going through this) –
Question – Why the hell I am reading about human eye and DSLR camera in a blog concerned with light setup in Unreal Engine?
Answer – It’s always important to understand basics that are concerned with lighting workflow irrespective of application and also Unreal Engine got this awesome “Eye Adaptation” already incorporated in the form of “Auto Exposure”. But to understand that properly, it’s important to get some basic idea first.
In Unreal Engine when we create a scene, which covers both exteriors and interiors simultaneously, controlling light balance becomes somewhat difficult due to variation in light intensities concerning exterior and interior environment. Also as character moves like a real human being in interactive environment, it’s wise to simulate human eye adaption in Engine itself to create realistic feel and workflow. All the information regarding the Auto exposure is given in the following link –
“Auto Exposure” settings are in the Post Process Volume.
“I will try to persuade EPIC to include Physical Camera settings in Engine. It will make the Engine’s Lighting workflow as per with other render engines, which in turn will be super easy to migrate and understand.”
Now as we have some basic understating about the exposure settings in the Engine, we will proceed with creating a simple scene only lit by HDRI. I am assuming that my readers have some basic knowledge of Unreal Engine, so will skip some fundamental steps.
Open Unreal Engine and create a new project by selecting “First Person Template”
In this project we will create a new “empty level” for our HDRI workflow (save it before starting work).
Now import your geometry/meshes into content folder of Unreal Engine (For more details about elaborate steps involved – see this tutorial)
Disable Auto Exposure from project settings
After that we will create “Lightmass Importance Volume” covering all of our meshes in the level which are going to render.
Next step will be of creating Box Reflection Capture wrapping entire meshes. This is very important for simulating correct reflections on objects inside and outside the building, you can also use large sphere reflection capture in exteriors (results want change that much).
Now it’s time setup HDRI as our environment background and create “Skylight” that will use the same HDRI for lighting but before that we have to import our HDRI into Engine. There are several methods to do so but we will go for the easiest one i.e. Drag and Drop.
I am using HDRI’s from – http://noemotionhdrs.net/ It’s one of the best free resource for HDRI.