Setting up textures downloaded from texture sites
From LuxRender Wiki
In this tutorial we will have a look at how to set up textures downloaded from texture sites. It is assumed that you are familiar with LuxRender and Blender and that you can add and modify materials. If this is new to you, please have a look at the introduction tutorial first. We will use LuxCore so please make sure that it is selected on the render tab. Grab the starter and finished files from here and extract the files somewhere.
The texture set used here is one of the free sets from Poliigon.com. Go ahead and download the Tiles 05 set. The file names used are for the 3K version but any one of them will do. Extract the files to the *blend file*\textures directory.
Let's take a look at the textures so we know what we have to work with.
Tiles05_COL_VAR1_3K.jpg - Diffuse texture Tiles05_COL_VAR2_3K.jpg - Diffuse texture Tiles05_DISP_3K.jpg - Displacement texture Tiles05_GLOSS_3K.jpg - Gloss/Specularity texture Tiles05_NRM_3K.jpg - Normal texture Tiles05_REFL_3K.jpg - Reflection texture
The two diffuse textures, displacement and normal textures can be used as they are. The glossy texture is the exact opposite of the roughness texture that LuxRender supports but we can easily convert it to a roughness texture. The reflection texture is the same thing as a specular texture, not to be confused with specularity.
Add a material for the plane, rename it to 'tiles' and click 'use material nodes'. In the node editor, replace the matte node with a glossy node. Add an image map node and connect it to the diffuse socket on the glossy node. Open Tiles05_COL_VAR1_3K.jpg in the image editor and unwrap the plane. Select the image in the image map node in the node editor. Set roughness to 0.001 and render.
As we saw earlier there is no roughness texture included in the texture set. But we can use the gloss texture and simply invert it. Add an image map node and open Tiles05_GLOSS_3K.jpg. To invert the gloss texture we add a math node, set its mode to Subtract and set Value 1 to 1.0. Connect the gloss texture node to Value 2 and the Math node to the Roughness socket on the Glossy node. Render.
As you can see the roughness is way too high since the highlights are gone. To lower the roughness we can add one more math node, set it to subtract and this time set its Value 2 to 0.96 and connect the first math node to Value 1 and connect the node to the Roughness socket on the glossy node. Render.
Note: When the math node is set to subtract, it will behave differently based on how you set Value 1 and 2. Flipping them will give very different results.
Duplicate(Shift-D) the image map node, open Tiles05_NRM_3K.jpg, enable the normal map option and connect the node to the bump socket. The default normal amount of this texture is too high as it will destroy all the highlights. We can tweak it by using the Height value, 1.0 being the texture's intended normal amount. Set the Height value to 0.1 and render.
The default specular color on the glossy node is RGB: 0.04 and that works fine in most cases. But the reflection texture is included in the texture set so let's put it to use. Add an image map node, open Tiles05_REFL_3K.jpg and connect the node to the specular color socket. Render!
You are of course not limited to using only the textures found in the set. You could just as well mix in a dirt map to break up the clean surface. For instance, mix two diffuse textures with the colormix node and mix roughness and normal/bump textures with the math node.
And as we did with the roughness texture, all textures can be tweaked a little without editing the actual image file.
HDRI: CC-BY OpenFootage.net