Before we get to making the Material, first we should gather some reference.
This is because it is usually best to start with multiple photo references that have multiple lighting situations so you can verify how the material looks under different lighting conditions.
If at all possible, having scanned and calibrated source data would be ideal as this will help to make sure that you are getting the best possible results.
When viewing your content inside the editor, make sure to disable the Editor Eye Adaptation for a more controlled environment: Edit Menu > Project Settings > Rendering > Default Post Processing Settings > Auto Exposure
A calibrated environment can be helpful in making sure that you get the colors correct but it is not required.
For the following example, we will be working with the Skin Rendering Content example.
If have not done so, please go ahead and download the Content Examples from the Marketplace now and open up the Skin Rendering Map.
Also please keep in mind that the images in this document are explicitly low resolution and are not meant to be used as source work.
It is extremely important that you make sure the Normal Map is correctly setup for use inside Unreal Engine. Some engines use a Normal Map where the green channel has been inverted. You can check to see if the green channel of your Normal Map has been inverted or not by comparing the colors in the following image to your Normal.
Here is a list of some things that you need to be aware of before you begin to create your Skin Textures and Materials.
Remember that when creating textures, it would be ideal if you start with very high resolution textures (e.g. 2Kx2K or higher) as this will give the best results.
For faster iteration, it is best to create a Material Instance and expose Scalar and Vector Parameters for faster and easier tweaking as the Material does not need to be recompiled during tweaking.
Keep in mind that assets should be verified in multiple lighting conditions to ensure that they are correct.
Even having Eye Adaptation enabled in the Post Process Volume can make a huge difference in how things look in the end.
To avoid shadow artifacts will require extra effort because you will need to tweak things like shadow bias or use a more focused spot light cone for better lighting resolution.
When tweaking, it might be useful to zoom in by adjusting the editor FOV as there will be no clipping through geometry and less distortions.
The editor Field Of View(FOV) can be adjusted by clicking on the Drop Down Arrow that is next to the icon that says Perspective and then adjusting the FOC value using the mouse.
When viewing your work, you might notice that the streaming system does not take the zoom into account and could blur your texture when you do not want to. This was an intentional design decision made for 3D games but this could change at some point in the future. To prevent this from happening, you can change the texture Streaming Distance Multiplier on the mesh instance.