editors note: Blender is a wonderful open source (free) software package that lets you draw objects, animate them, and create very realistic views. This is done by defining surface properties, and the software calculates how light would reflect from it. The software is used by many animation studios and professional graphic artists. It is available from http://www.blender.org
Here is part 2 of my overview on using Blender to make a rather basic 3D animation. Part 1, which includes a few tips and thoughts on modelling can be found here: http://fltechtoybox.org/blog/introduction-blender-part-1
Once you have all of your objects modeled, the real fun begins. It turns out that making realistic materials is more art and less science. At first, I was making pretty awful-looking materials but after watching a few tutorials and experimenting quite a bit, things began to look decent.
Materials and Lighting
Coming into this, I knew essentially nothing about rendering so for a long time I was using Blender’s default “Blender Render” engine. In general, a new user will want to use the “Cycles” raytracing-based render engine. Due to the way it calculates the paths of light, Cycles makes things look incredibly realistic without too much required knowledge from the user. You can switch to Cycles in the “info” tab at the top by clicking on the selector that has “Blender Render” showing as default.
Creating realistic materials with Cycles can be very easy depending on the material. Before doing so, you will want to create a light source. Blender includes light sources, such as a lamp, by default. As I understand it, it is actually easier to use objects with an “emission” material as your source of light. This is because light typically does not come from a single point and it is better to have something resembling an actual light bulb to achieve realistic renders.
For a large number of materials, the built-in surfaces are excellent (diffuse, transparent, velvet, etc.). I ended up using a lot of materials that used only a single surface setting. However, if you need something that interacts with light sources in multiple ways you will want to use the “mix shader” setting. I often mixed Diffuse BSDF with Glossy BSDF if I wanted a material that looked like plastic or metal. Here is an example of settings I used to create a black plastic material that I thought turned out particularly well:
At first I tried to learn everything by doing, but watching a lot of tutorials turned out to be a much more efficient use of my time especially with materials and lighting. If you are a novice, do yourself a favor and watch some tutorials on www.blenderguru.com and @tutor4u’s youtube channel.
Something that I found rather difficult to learn was how to use an image as a material. As it turns out, it is an easy matter but you need to do a few things that might not be immediately obvious. As an example, I’ll go through a tutorial of how to give a desk a wooden texture.
1. Assuming you’re starting with a 3D view editor, select the desk and enter edit mode (press Tab)
2. If you haven’t done so, click on the material tab of the object’s properties
3. Add a new material if necessary. I chose to use Diffuse BDSF for my surface but a more realistic surface might include some reflection.
4. For the color, click on the dot that is enclosed by a red box in my picture below and select “Image Texture”
5. Click on the button labelled “Open,” navigate to the desired image texture and then select it
6. Drag open a new window in the 3D view editor and change it to “UV/image editor” (this is done by clicking on the top-right corner where there are 3 lines at a 45° angle)
7. Select the image using the tab selector enclosed by an orange box in my picture below
8. Go back to the 3D view and make sure that the faces you would like to have this image texture are selected. In my case, I simply pressed “a” to select all faces. If you want to have multiple materials on a single object, you will need to use the "Assign" button with the desired faces selected.
9. In the 3D view, press “u” and select “Unwrap.” You should see a series of rectangles appear on the image in the UV/image editor view. The vertices of these rectangles can be moved to your heart’s desire to affect how the image is projected on the surface of your object.
If the above image is difficult to see, open it in a new tab or just download it to see it at full size.
Those are the basics of the matter. There are more powerful mapping methods available if you need them. I didn’t find it necessary to use anything beyond the Unwrap function but more advanced techniques are required for rendering with more realism (and therefore complexity).
Once you have all of your objects modeled and painted, so to speak, you are ready to begin plotting the animation! I will leave that to part 3 of this series, which can be found here.