HOW CAN I CREATE PBR MATERIALS IN UE4?
Courtney Dennett, Birmingham
With the release of Unreal Engine 4 came a whole new way to think about and create our archviz projects. I will take you through a few easy steps for creating PBR materials in Unreal Engine so we can work with them as we usually do with other software like V-ray and Corona.
01 TEXTURES AND NEW MATERIAL
The first step is to load our textures in Unreal Engine; we need to create a folder to store our files so that Unreal can access them. Once we have our textures we have to create our material and name it MASTER. Open it and hold and drag the textures we will use. Once placed, change each one to Parameter (right-click, Convert to Parameter) and name each accordingly: Diffuse (Diffuse map), Roughness (AO map) and Normal (Normal map).
02 DIFFUSE
Next we need to add all the variables we need. We will go for Diffuse first, and we will add a variable that will enable us to change the size of the texture in the polygon. Press M and right-click, and MULTIPLY will show. Now press S and click so we can add a PARAMETER. Set its default value to 1 and name it UV SIZE. This is the one we will change. Press U, right-click and we will have TEXCOORD. Connect this to MULTIPLY in A, UV SIZE in B, and then connect the MULTIPLY to the Base Color. Apply and save the changes.
Close the material and create an instanced material. Open it and you will see a value called UV SIZE, and that would be the value we set in the slate of the material so we can change the size. Now it’s time to add more elements so we can change the position in X and Y. Open the MASTER material. Press A and ADD will appear, then right-click and type APPEND VECTOR. Select it and press S so we can have a PARAMETER. Here is where we will change the values. Name it UV X, create
another and name it UV Y, set both default values to 1 and connect them to APPEND, X in A and Y in B.
Connect APPEND to ADD in B and now we will connect the TEXCOORD we placed before in ADD A. Then we need to connect ADD to MULTIPLY A, apply, save and open the instanced material, and we will now have UV X and UV Y values. Check each one and you will be ready to change the values and see how it affects the material.
03 ROUGHNESS
Now we are going to add another option to our material, this time enabling us to change the strength of the roughness. Press M and right-click to add a MULTIPLY, and click S and right-click to add a PARAMETER (set its default value to 1 and name it ROUGHNESS). Connect the ROUGHNESS TEXTURE to MULTI A, and connect the ROUGHNESS to MULTI B. Finally connect MULTI to the ROUGHNESS in our master material. Apply and save, and if you open the instanced material we will now have the roughness value available.
04 NORMAL
Next we need to tweak the Normal map. Press 3 and search for a Materialexpressionconstant3vector.
Set its values to 0,0,1, now press S and click to add another PARAMETER. Set its default value to 1 and name it NORMAL STRENGTH. Press L, then right-click and we will have a LERP – this will help us reduce or increase the strength of our normal texture. Connect NORMAL STRENGTH to ALPHA, the Materialexpressionconstant3vector to A, and finally connect our normal texture to LERP B. Apply and save.
Go to the instanced material and you’ll see how all the modifiers we need are available and are similar materials as those from other render engines. Now go ahead and change the different values to see how they work!