Welcome to the third tutorial of the Blender Basics tutorial series. In this tutorial we will be looking at materials in Blender.
Blender Reference Manual – https://docs.blender.org/manual/ja/dev/index.html
Blender Hotkeys Reference – https://wiki.blender.org/index.php/Doc:2.4/Reference/Hotkeys/All
Textures can add realism to the materials used on objects in Blender. We are going to begin by adding a simple texture to help understand the process of texturing in Blender.
Make sure the Cube is selected and then open the Materials panel. Let’s change the Diffuse color to a light blue. This will gives us a solid color but if we want something richer we need to use a texture.
Let’s open the Textures panel (checkerboard icon). At the top of the panel we see that we have slots for multiple textures. For now we are going to stick with the default texture – Tex. Type allows us to choose the type of texture we want to apply. We have the choice of using anything from clouds to wood or even our own environment map or image or movie. Each one of these types has their own parameters and customizability.
Let’s choose Marble from the list. If we go into Rendered view we can see that the texture is already applied to our cube. The fuchsia color comes from the Influence section. This color can be changed if we wish but we will just leave it on the default. The texture is acting like an alpha channel. The fuchsia color is showing up where the white is located on the texture and the original blue color is showing up where the black is located on the texture.
If you notice under the Influence section, Color is checked. Influence by default affects the color. If we turn Color off, notice that the Texture is now hidden. If we turn the Color back on and change the influence to 0.500 the Texture is affecting the color but only at half-strength and if we change it to 1.000 the Texture is affecting the color at full-strength.
Emit affects the value of the shade and makes itself illuminate where it is white and keeps the standard color where it is black. If we check Emit and turn Color off this becomes evident. We can also affect Specular just like we have already seen earlier. Geometry can also be affected in this section. If we turn on Normal and Color and turn off the Emit, we now notice that the Texture becomes a normal map – creating bumps on the surface of the Cube.
Blend determines how the Texture blends with the original Diffuse color. We have multiple options with Mix being the default. If we are familiar with Photoshop or a similar program some of these options will be familiar.
If we go back to the Materials panel we will now notice that the Texture is being applied to our original Material.
Now let’s look at how to use image maps as part of a texture.
Let’s go back into the Texture tab and remove the marble texture from the Cube. Now we do not have any textures on the Cube. Click on the second slot (below Tex) and hit the “New” button and change the Type to Image or Movie. In the Image section we need to click on “Open” and open up a bitmap. (I’m using a polka-dot pattern which can be found on Public Domain Pictures [link is in the description]).
The texture is now applied to the Cube but it is stretched. This is part of the problem of trying to wrap a 2D texture around a 3D object. What we need to do is map the 2D texture to the 3D model. This can be done under the Mapping section.
If we change the Coordinates to Object we can now see that the stretching has been fixed. We must realize though that depending upon the object, the Coordinates option may need to be set to UV or one of the other options.
Another way to texture an object is via the UV Editor.
Let’s delete the texture from the Cube by clicking on the “X” next to “Texture.” Click “New” and add a new Image or Movie Texture to the Cube. (I’m using a vintage paper pattern which can be found on Public Domain Pictures [link is in the description]).
Let’s split the screen into two vertical areas and change the right-hand-side to UV/Image Editor.
Make sure the Cube is selected and tab into Edit Mode (make sure you are in Orthographic Mode (5 on the Numpad)). We now need to make seams on the Cube so we can unwrap the Cube onto the UV map. Use the shortcut CTRL TAB and make sure we are in Edge Mode. We need to choose the top-front edge and the c-shaped edges on the two sides using SHIFT-RIGHT-CLICK. Once all seven edges are selected use the shortcut CTRL E to access the Edges menu and select Mark Seam.
Now, hit the A key twice to make sure that the Cube is selected. Now hit the U key and choose unwrap. If the unwrapping is crooked we can use the R key for rotation and the G key to move the UV and make sure it is straight. Click on the folder and open up the image.
Tab back into Object Mode and select the Lamp and change it to Hemi so we have better lighting. Now select the Cube and tab back into Edit Mode and then choose Rendered. We can now see that the Texture is mapped onto the Cube.
The pattern is pretty large and if we want a simple, quick way of making the pattern smaller we can make the actual UV of the Cube larger. If we hit the S key we can resize the UV and if we look at the Rendered Cube we can now see that the pattern is smaller.
Bump and Normal Maps
We can also make normal maps that will allow us to create the illusion of a rough surface.
Let’s start with a clean scene by going to File > New > Reload Startup File. Make sure the Cube is selected and then go to the Materials tab and put a light brown Diffuse color on the Cube. Go to the Texture tab and choose the first slot in the Texture stack (Tex) and change the Type of Stucci. Now when we go into Rendered Mode we now see stripes going around the Cube.
Now let’s make a Normal Map out of this flat Stucci Texture. Under the Influence section turn on “Normal” under the Geometry section. We now see bumpy stripes going around the Cube in Rendered Mode.
Note that Normal Maps work best on objects that are high poly – meaning that they have a lot of geometry.
Normal Maps make the object appear to have a bumpy surface but they don’t actually change the surface of the object. If we want to actually change the surface of the object we need to use a Displacement Map.
Let’s start with a clean scene by going to File > New > Reload Startup File. Make sure the Cube is selected and tab into Edit Mode. If we are going to use the Displacement Map we need to have enough geometry to make it work. Go to the Tool Panel and select Subdivide and change the Number of Cuts to 15.
Let’s go to the Materials tab and add a light-yellow Diffuse color to the Cube. Then, under the Texture tab let’s change the default Texture to Clouds. If we then go to the Influence section – under Geometry – we need to turn on the Displace option. Now, if we go into Rendered mode we can see how the Cube’s geometry has been changed.
Remember that Normal Maps is a surface effect which doesn’t change the actual geometry of the object. Displacement Maps however change the actual geometry of the object.
Another way to create textures for objects in Blender is to use the Node Editor.
Let’s start with a clean scene by going to File > New > Reload Startup File. Let’s then split our view into two separate horizontal areas. Let’s change the top area into a Node Editor. What we want is to add a Texture to the Cube. So, we need to change to the Texture option (checkerboard pattern) and the check Use Nodes. We now see two nodes – one for texture and the other for the output.
These Nodes are actually connected to the Texture panel that we have been using. If we go to the Texture panel we notice that the same red and white checkboard pattern showing in the Nodes is listed there as well. If we go into Rendered view we see that the Texture is actually applied to the Cube via the Output Node.
We can also add Nodes and make changes to the Textures.
Let’s make the Checker Node is active by right-clicking on it and deleting it. Notice that our Cube is now dark because there is no Texture attached to the Output Node. If we click on Add and Textures you notice that we have the same Textures that we have already seen earlier. We also have Patterns available to us.
Let’s go ahead and choose Bricks from the Pattern menu. Now all we need to do is left-click and connect the Color output from the Bricks Node to the Color input in the Output Node. Notice that we can now see the Pattern on the Cube. We can change the colors of the bricks and mortar as well as the thickness of the mortar.
We can also do things like add a Texture to the Pattern. Let’s go to Add > Texture > Stucci. Now all we need to do is left-click and connect the Color output from the Stucci Node to the Color input in the Bricks Node. Notice that we can now see the Texture and the Pattern on the Cube.
So as you can see, there are a lot of possibilities here. You can certainly plug nodes into other nodes, so it’s a really great way to create highly custom textures and materials.