Creating Rocks and testing Materials

This time I have tried to improve my material skills, using the node editor. To further improve my skills in the node editor, I have consulted a blender conference video "

Materials Made Easy - Non-Destructive Shading in Blender", that you can check here.

It belongs to the Official Blender Youtube Channel.

To quickly model rocks, a similar workflow of the one shown in the video above was used. 

Start with a simple extruded cube.  

Then, add a subdivision surface to make it smooth. 

Add a displace modifier with a Voronoi texture with large displacement scale, to give the base rock mesh. 

Then, add a second subdivision surface modifier, to smooth out those weird edges from the displace modifier. At last, add a displace modifier with a second Voronoi texture, with smaller details. This gives the rock a more realistic look, without having to actually model a realistic one.

On the modifiers tab you should end with something like this:

Skills/Shortcuts learned:

Go to "Edit->Preferences->Add-ons->Activate Node Wrangler"

Node Wrangler has a lot of useful shortcuts to use in the Node Editor.

Shortcuts and Nodes used in the setup of the realistic materials:

Select the "Image Texture Node" press Ctrl + T to add the "Texture Coordinates" and "Mapping Node" attached to the image texture. This allows us to quickly change the scale, position, and rotation of the texture.

By selecting 2 nodes and pressing F you can connect them.

Select multiple nodes and press Ctrl + J to join them inside a Frame. Press N and change label, frame name, and color. Useful to group nodes inside containers and keep track of changes.

To preview the effect of the active node, select a node with Ctrl + Shift + LMB click on top of the node. The Node Wrangler addon will create a preview node and output the effect of that node into the active mesh. 

Now let's check the node editor setup, step by step to achieve a realistic rock material

Start with the basic Image Texture, then Ctrl + T on top of it to add the Mapping node and Texture Coordinates

Now let's check the rest of the node editor

The bump map uses the normal directions from the mesh, and give a fake sense of height and depth to the applied texture. 

The roughness map tells the shader which parts of the mesh will be shiny/polished and which will be rough. 

The noise texture was used, in combination with the Hue/Saturation Node to create subtle spots with a different color on the rock.

And with this, we got the final result: 

Another angle:

Now let's add moss to the top of the rock.

We have the node setup shown below. Start with the same procedure, having the rock texture, mapping, and coordinates nodes. We have a second texture image of grass, you can use another one if you like.

Rock Texture:

Grass Texture:

The grass texture passes trough a Hue/Saturation Node to improve the green intensity of the grass.

By mixing the rock texture image with the grass texture, using a Mix RGB node, we would have a mixed effect of 50% grass, 50% rock. We only want the grass to appear on top of the rock, so we make clever use of normals to use as a factor for the Mix Node.

Normal maps from the Texture Coordinates Node:

If we only select the Green Channel, using a Separate RGB Node, We can select only a portion of the rock to be affected. We improve the effect with a ColorRamp Node.

After connecting this effect as a Factor for the Mix RGB Node, we have the following result:

After that we use a color ramp to select the roughness map, giving it a realistic reflection. The Bump Node is also used to give the perception of depth and height to the rock.

Final Result