Blender 2.6 Cycles: Materials and Textures Cookbook: With this book you'll be able to explore and master all that the Cycles rendering engine is capable of. From the basics right through to refining, this is a must-read if you're serious about the realism of your materials and textures.

In the upper menu bar, switch from Blender Render to Cycles Render (hovering with the mouse on this button shows the Engine to use for rendering label).

Now split the 3D view into two horizontal rows and change the upper one in to the Node Editor window by selecting the menu item from the Editor type button at the left-hand corner of the bottom bar of the window itself. The Node Editor window is, in fact, the window we will use to build our shader by mixing the nodes (it's not the only way, actually, but we'll see this later).

Put the mouse cursor in the 3D view and add a plane under the cube (press Shift + A and navigate to Mesh | Plane). Enter edit mode (press Tab), scale it 3.5 times bigger (press S, digit 3.5, and hit Enter) and go out of edit mode (press Tab). Now, move the plane one Blender unit down (press G, then Z, digit -1, and then hit Enter).

Go to the little icon (Viewport Shading) showing a sphere in the bottom bar of the 3D view and click on it. A menu showing different options appears (Bounding Box, Wireframe, Solid, Texture, Material, and Rendered). Select Rendered from the top of the list and watch your cube being rendered in real time in the 3D viewport.

Now, you can rotate or/and translate the view or the cube itself and the view gets updated in real time (the speed of the update is only restricted by the complexity of the scene and by the computing power of your CPU or of your graphic card).

Let's learn more about this:

Select Lamp in the Outliner (by default, a Point lamp).

Go to the Object Data window under the Properties panel on the right-hand side of the interface.

Under the Nodes tab, click on Use Nodes to activate a node system for the selected light in the scene; this node system is made by an Emission closure connected to a Lamp Output node.

Go to the Strength item, which is set to 100.000 by default, and start to increase the value—as the intensity of the Lamp increases, you can see the cube and the plane rendered in the viewport getting more and more bright, as shown in the following screenshot:

Select the cube to assign the shader to, by left-clicking on the item in the Outliner, or also by right-clicking directly on the object in the Rendered viewport (but be aware that in Rendered mode, the object selection outline usually around the mesh is not visible because, obviously, it's not renderable).

Go to the Material window under the Properties panel: even if with the default Factory Settings selected, the cube has already a default material assigned (as you can precisely see by navigating to Properties | Material | Surface). In any case, you need to click on the Use Nodes button under the Surface tab to activate the node system; or else, by checking the Use Nodes box in the header of the Node Editor window.

As you check the Use Nodes box, the content of the Surface tab changes showing that a Diffuse BSDF shader has been assigned to the cube and that, accordingly, two linked nodes have appeared inside the Node Editor window: the Diffuse BSDF shader itself is already connected to the Surface input socket of a Material Output node (the Volume input socket does nothing at the moment, it's there in anticipation of a volumetric feature on the to-do list, and we'll see the Displacement socket later).

Put the mouse cursor in the Node Editor window and by scrolling the mouse wheel, zoom in to the Diffuse BSDF node. Left-click on the Color rectangle: a color wheel appears, where you can select a new color to change the shader color by clicking on the wheel or by inserting the RGB values (and take note that there are also a color sampler and the Alpha channel value, although the latter, in this case, doesn't have any visible effect on the object material's color):

The cube rendered in the 3D preview changes its material's color in real time. You can even move the cursor in the color wheel and watch the rendered object switching the colors accordingly. Set the object's color to a greenish color by setting its RGB values to 0.430, 0.800, and 0.499 respectively.

Go to the Material window and, under the Surface tab, click on the Surface button, which at the moment is showing the Diffuse BSDF item. From the pop-up menu, select the Glossy BSDF shader item. The node now also changes in the Node Editor window and so does accordingly the cube's material in the Rendered preview, as shown here:

In the Material window, under the Surface tab, click again on the Surface button that is now showing the Glossy BSDF item and replace it back with a Diffuse BSDF shader.

Put the mouse pointer in the Node Editor window and, by pressing Shift + A on the keyboard, make a pop-up menu appear with several items. Move the mouse pointer on the Shader item, it shows one more pop-up where all the shader options are collected.

Select one of these shader menu items, for example, the Glossy BSDF item. The shader node is now added to the Node Editor window, although not connected to anything yet (in fact, it's not visible in the Material window but is visible only in the Node Editor window); the new nodes appear already selected.

Again press Shift + A in the Node Editor window and this time add a Mix Shader node.

Press G to move it on the link connecting the Diffuse BSDF node to the Material Output node (you'll probably need to first adjust the position of the two nodes to make room between them). The Mix Shader node gets automatically pasted in between, the Diffuse node output connected to the first Shader input socket, as shown in the following screenshot:

Left-click with the mouse on the green dot output of the Glossy BSDF shader node and grab the link to the second input socket of the Mix Shader node. Release the mouse button now and see the nodes being connected.

Because the blending Fac (factor) value of the Mix Shader node is set by default to 0.500, the two shader components, Diffuse and Glossy, are now showing on the cube's surface in equal parts, that is, each one at 50 percent. Left-click on the Fac slider with the mouse and slide it to 0.000. The cube's surface is now showing only the Diffuse component, because the Diffuse BSDF shader is connected to the first Shader input socket that is corresponding to a value set to 0.000.

Slide the Fac slider value to 1.000 and the surface is now showing only the Glossy BSDF shader component, which is, in fact, connected to the second Shader input socket corresponding to a value set to 1.000.

Set the Fac value to 0.800. The cube is now reflecting on its sides, even if blurred, the white plane, because we have a material that is reflective at 80 percent, matte at 20 percent, and so on:

Lastly, select the plane, go to the Material window and click on the New button to assign a default whitish material.

Go to the Render window under the Properties panel. In the Sampling tab, set Samples to 100 both for Preview and Render (they are set to 10 by default).

Set the Clamp value to 1.00 (it's set to 0.00 by default). Go to the Light Paths tab and set the Filter Glossy value to 1.00 as well. The resulting rendered image, as shown here, is now a lot more smooth and noise free:

Save the blend file in an appropriate location on your hard drive with a name such as start_01.blend.

Starting from the previously saved start_01.blend blend file, where we already had set a simple scene with a cube on a plane and a basic material, select the cube and go to the Object Modifiers window under the Properties panel to the right of the UI.

Assign to the cube a Subdivision Surface modifier, set the Subdivisions level to 4, both for View as for Render.

In the Object Tools panel to the left of the 3D window, under Shading, set the subdivided cube (let's call it spheroid from now on) to Smooth.

Just to make things clearer, click on the color box of the Glossy BSDF shader to change it to a purple color (RGB set to 0.800, 0.233, and 0.388 respectively). Note, only the glossy reflection part on the spheroid is now purple, whereas the rest of the surface, the diffuse component, is still greenish.

Save the blend file and name it start_02.blend.

Put the mouse pointer in the Node Editor window and press Shift + A.

In the contextual menu pop-up, go to the Texture item, just under Shader, and left-click on Wave Texture to add the texture node to the Node Editor window.

Grab and connect the Color yellow output socket of the texture to the yellow input socket of the Diffuse shader, the one close to the Color rectangle that we had formerly set as a greenish color:

In the Wave Texture node, change the Scale value to 8.500, Distortion to 12.000, Detail to a maximum value of 16.000, and the Detail Scale value to 6.000.

Now disconnect the texture color output from the Diffuse node and connect it to the color input socket of the Glossy shader:

Now disconnect the texture color output from the Glossy shader. Grab and connect the texture node's Fac output to the Roughness input socket of the Glossy BSDF shader, as shown in the following screenshot:

Save the file.

Delete the Wave Texture node (X key), press Shift + A with the mouse pointer in the Node Editor window and add a Checker Texture node.

Connect the Fac output of the Checker Texture node to the Fac input socket of the Mix Shader node, as shown here:

Save the file as start_03.blend.

Press Shift + A on the keyboard with the mouse pointing in the Node Editor window again, go to the Input item and select the Texture Coordinate item, which is a node with several mapping modes and their respective output sockets.

Try to connect the several outputs to the Checker Texture | Vector input (the blue socket on the left-hand side of the node) to see the texture mapping on the spheroid change in real time, as shown in the following screenshot:

Go in the UV Maps tab in the Object Data window under the Properties panel on the right and click on the + sign. This just adds a one-to-one Reset UV projection UV layer to the object, that is, every face of the mesh is covering the whole area of the UV window (remember that although the cube looks like a spheroid now, this is only due to the effect of the assigned Subdivision Surface modifier; the UV coordinates work at the lowest level of subdivision, which is still a six-face cube).

A second option is to just place the proper seams on the cube's edges and directly unwrap the object in an UV/Image Editor window. Press Tab to go to edit mode, press A to select all the vertexes (if the vertexes are deselected). Now, press U and chose an unwrapping method from the pop-up menu (Smart UV Project and Cube Projection don't even need the seams), then go out of edit mode to update the Rendered preview.

Select the Texture Coordinate node and grab it to the left of the window, as far as suffices to make room for a new node. In the Add menu, go to Vector and choose Mapping.

Grab the Mapping node on the middle of the link that is connecting the Texture Coordinate node to the Checker Texture node; it will be automatically pasted in-between them, as shown in the following screenshot:

Now, start playing with the values inside the Mapping node. For example, set the Z Rotation value to 45°, the X Scale value to 2.000 and then slide the X Location value, while looking at the texture changing orientation, dimension and actually sliding on the x axis in the Rendered viewport.

Save the blend file as start_04.blend.

Open the start_04.blend file and go to the World window under the Properties panel to the right of the interface. This is where we see the usual Use Nodes button under the Surface tab.

Although no node system for the World window is set by default, the World window has a dark medium gray color already slightly lighting the scene. Delete the default lamp or put it on a different and disabled layer to see that the spheroid in the scene is dark but still visible in the rendered 3D viewport.

It's already possible to change this gray color to some other color by clicking on the Color button right under Use Nodes (color at the horizon). This brings up the same color wheel we have seen for the shader colors. Set the color to R 0.179, G 0.152, and B 0.047 and save the file as start_05.blend.

Look in the bottom header of the Node Editor window, on the left-hand side of the material datablock, there are two little icons: a little cube and a little world and, yes, the cube icon is used for creating materials, while the world icon is for the World window. At the moment, because we were working on the spheroid material, the cube icon is the one selected.

Click on the little world icon. The material's node disappears and the Node Editor window is empty now, because we entered the World mode. Check the little Use Nodes box on the right of the datablock to make a default world material appear. Or else, go to the World window under the Properties panel and click on the Use Nodes button under the Surface tab, as shown here:

Also, for the World, the default material is simply made up of two nodes: a Background node connected to a World Output node. In the Background node, there are two setting options: the Color box and the Strength slider, both of which are quite self-explanatory.

Go to the World window under the Properties panel and click on the little square with a dot to the right side of the Color slot. From the resulting menu, select the Sky Texture node item. This replicates a physical sky model, with an atmospheric Turbidity value slider and the Strength slider, as shown here:

Note that you can also modify the incoming direction of the light, that is, the location of the sun, by rotating the sphere icon inside the node interface.

Save the file as start_06.blend.

Click on the Color button, which is now labeled as Sky Texture under the Surface tab in the Properties panel and select the Environment Texture node to replace it:

Looking in the Rendered view, you'll see that the general lighting has turned to a pink color. This is to show that the World material is now using a texture to light the scene, but that at the moment there is no texture yet.

Click on the Open button both in the World window under the Properties panel or in the just added node inside the Node Editor window. Browse to the texture folder and load the Barce_Rooftop_C_3k.hdr image (a free high dynamic range image licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 License from the sIBL Archive http://www.hdrlabs.com/sibl/archive.html).

To better appreciate the effect, click on the little eye icon on the side of the Lamp item in the Outliner to disable its lighting. The spheroid is now exclusively lit by the .hdr image assigned to the World material. Actually, you can also see the image as a background in the Rendered preview. You can also rotate the viewport and watch the background texture, "pinned" to the World coordinates, rotate accordingly in real time.

As for object's materials, the mapping of any texture you are going to use for the World can be driven by the usual Mapping and Texture Coordinates nodes we have already seen. Generally, for the World materials, only the Generated coordinates output should be used, and actually it's the one used by default if no mapping method is specified. Add the Mapping and Texture Coordinates nodes and connect them to the Vector input socket of the Environment Texture node, as shown in the following screenshot:

Save the file as start_07.blend.

One way is to go in the Render window and, under the Film tab, check the Transparent option. This will show our spheroid and plane rendered both in the 3D viewport as well as in the effective final rendered image on a transparent background, that is, with a pre-multiplied alpha channel:

It's enough, then, to compose the rendered objects with a blue background image, both in an external image editing software (such as The Gimp, to stay inside F/OSS) or directly in the Blender compositor.

If it's the case, uncheck the Transparent box in the Render window to restore the sky in the preview and in the render.

Left-click the World Output node in the Node Editor window, and press G and move it to the right.

Add a Mix Shader node (press Shift + A and select Shader |Mix Shader) and move it to the link connecting the Background node to the World Output node, to paste it automatically between the two nodes. Connect it to the Surface input socket of the World Output node.

Select the Background node in the Node Editor window. Press Shift + D to duplicate and move it down.

Connect its output to the second input socket of the Mix Shader node. Click on its Color box to change the color to R 0.023, G 0.083, and B 0.179.

Now, add a Light Path node (press Shift + A and go to Input | Light Path).

Connect the Is Camera Ray output of the Light Path node to the Fac input socket of the Mix Shader node, and voilà—the objects in the scene are lit by the hdr image connected to the first Background node, but they appear on a "sky" that is colored as set in the Color box of the second Background node:

Save the file as start_08.blend.

Starting from the start_07.blend file, click on the eye lamp icon in the Outliner to enable it again.

Right-click the lamp in the 3D view and press Shift + S to bring up the Snap menu. Left-click on the Cursor to Selected item.

Press Shift + A with the mouse pointer in the 3D view and add a plane to the scene at the cursor's location.

Come out of edit mode (press Tab). Shift select the lamp; now you have both the just added plane and the lamp selected, and the latter is the active one.

Press Crtl + C to bring up the Copy Attributes menu and select the Copy Rotation item.

Rename this plane to Emitter.

Right-click the lamp in the 3D view and press X to delete it.

Put the mouse pointer in the 3D view and press 0 from the numpad to go to Camera view.

From the Viewport Shading menu in the window header, select the Rendered mode:

Save the file as start_09.blend.

Select the Emitter plane and click on the little cube icon on the header of the Node Editor window.

Click on the New button in the header and rename the material as Emitter.

In the Properties panel, go to the Material window and under the Surface tab, click on the Surface button to switch the Diffuse BSDF shader with an Emission shader. Leave the default color unchanged (RGB 0.800) and set the Strength slider to 35.000.

Save the file.

In the 3D view, scale the Emitter plane five times bigger (press S, digit 5, and hit Enter), then set the Strength slider to 3.500.

Save the file as start_10.blend.

Now let's scale the Emitter plane a lot smaller (press S, digit 0.05, and hit Enter) and set the Strength slider to 350.000.

Save the file as start_11.blend.

Start with the last saved blend (start_11.blend) with the 3D window on the left also set to the Rendered mode, to see the scene out of the Camera view (so the Emitter plane is rendered too).

With the Emitter plane still selected, go to the Object window under the Properties panel.

Look in the Ray Visibility tab (usually, at the bottom of the Properties window), where there are five items: Camera, Diffuse, Glossy, Transmission, and Shadows with corresponding checked boxes.

Uncheck the Camera item and watch the Emitter plane disappear in the rendered 3D window, but the scene still lit by it, as shown in the following screenshot:

By checking any one of the items, the corresponding property won't take part in the rendering. In our case, by unchecking the Camera box, the mesh won't be rendered, although still emitting light. Be careful that, at this moment, the Emitter plane is not renderable but, because all the other items in the tab are still checked, it can be reflected, and if this is the case, can cast its own shadow on the other objects.

Now reselect the spheroid (remember that, unless you have renamed it, its name in the Outliner still shows as Cube). Next, from the Ray Visibility tab in the Object window under the Properties panel, uncheck the Camera item as well.

Now the spheroid has disappeared, but it's still casting its shadow on the plane, as shown in the following screenshot:

Now uncheck the Camera and the Shadow checkboxes. In this case, the spheroid is visible again but is not casting any shadow, as shown here:

Save the file as start_12.blend. Let's try tweaking this a little.

Check the Shadow box for the spheroid and select the bottom plane.

In the Material window under the Properties panel, switch the Diffuse BSDF shader with a Glossy BSDF shader. The bottom plane is now acting as a perfect mirror, reflecting the spheroid and the .hdr image, which we had formerly set in the World material.

Go back to the Object window and reselect the spheroid. In the Ray Visibility tab, uncheck the Glossy item and watch the spheroid still rendered but no more reflected by the mirroring plane, as shown here:

Save the file as start_13.blend.

Open the 1301OS_01_meshlight.blend file, which has a prepared scene similar to the one used for the preceding screenshots, and set the bottom 3D window to the Rendered mode by clicking on the Viewport Shading button in the header and selecting the upper item.

Left-click the Emitter item in the Outliner and put the mouse pointer in the Node Editor window. Add a Mix Shader node (press Shift + A and go to Shader | Mix Shader) and move it to the link connecting the Emission node to the Material Output node to paste it in between.

Add a Geometry node (press Shift + A and go to Input | Geometry) and connect its Backfacing output to the Fac input socket of the Mix Shader node.

Switch the Emission node output from the first Shader input socket of the Mix Shader node to the second one, as shown in the following screenshot:

Save the file as 1301OS_01_meshlight_final.blend.

Open the start_02.blend file and set the 3D view to the Rendered mode.

Put the mouse pointer in the Node Editor window and press Shift + A to bring up the Add menu and select a Math node from the Convertor item (press Shift + A and go to Convertor | Math).

Connect the Fac output of the Wave Texture node, already connected to the Roughness input socket of the Glossy BSDF shader node, to the first upper gray Value input socket of the Math node. Connect the Math node output to the Displacement input socket of the Material Output node.

Set the operation mode of the Math node to Multiply. By sliding the second Math node Value, we can set the influence, the strength, of the bumping. Try, for example, to set it to 3.000, as shown in the following screenshot:

Save the file as start_14.blend.

Starting from the start_14.blend file, select the Math node in the Node Editor window and delete it (press X).

Put the mouse pointer in the Node Editor window and press Shift + A to add a Bump node (press Shift + A and go to Vector | Bump).

Connect the Fac output of the Wave Texture node to the Height input socket of the Bump node and the output of the latter to the Normal input socket of the Diffuse BSDF shader node. Set the Strength value to 0.050.

Add a Voronoi Texture node (press Shift + A and go to Texture | Voronoi Texture) and a new Bump node (press Shift + A and go to Vector | Bump). Connect the Fac output of the Voronoi Texture node to the Height socket of the new Bump node and connect the latter to the Normal input socket of the Glossy BSDF shader node:

Save the file as start_15.blend.

Go to the Render window under the Properties panel. In the Render tab click on the Feature Set button, by default labeled with Supported, and select Experimental.

Go to the Object Data window to find a new tab named Displacement, where we can choose between three options: Bump, True, or Both (the Use Subdivision and Dicing Rate buttons don't seem to work yet).

Select True.

Reselect the spheroid. Go in the Material window under the Properties panel, and in the Displacement tab click on the blue Value button labeled Wave Texture to select an Image Texture node from the pop-up menu.

Click on the Open button, browse to the textures folder, and load the quads.png image.

Just under the Open button, click on the Color Space button to set it to Non-Color Data.

Split the bottom 3D window to open a UV/Image Editor window. Press Tab to go in edit mode and then press U with the mouse pointer in the 3D window. In the UV Mapping menu, select Smart UV Project, then press Tab again to go out of edit mode (this is a quicker way of unwrapping the spheroid which, remember, at its lower level of subdivision is still a cube. If you want, you can do a better unwrapping by placing seams to unfold it and by selecting a normal Unwrap from the menu).

Go to the Object Modifiers window and raise the Subdivisions levels for both View and Render to 6: