Ceci est une ancienne révision du document !
Last month we used Cycles Render to create the image shown below left.
Let’s create a similar image (below right) with the Blender engine.
The first thing that we notice (at least me) is shadows. The shadows that our point lamp casts, with blender render, are almost black. This phenomenon is happening because in Blender renderer, the light is been emitted by the lamp only. This isn't realistic, as in the real world every object emits or reflects light.
On the other hand, Cycles renderer calculates the light that every object has from the surroundings. You can observe the cone and see how the shadow from the cube smoothly fades (contrary to the cone from the Blender renderer), and we have a mirroring ground and a shiny metal cube in our scene.
One other thing that is very crucial, and a main difference between Blender and Cycles, is more technical.
Navigate to File > User Preferences > System (above).
At the lower left corner of the System Tab you can check if your computer has Nvidia CUDA support under Compute Device
My GPU has CUDA support so I can enable it. You can also check it at the official CUDA support url: https://developer.nvidia.com/cuda-gpus
If you are lucky and have an Nvidia CUDA card, you have to enable it under the Compute Device Tab that I mentioned before AND under the Properties Panel, Render Tab → Device → GPU Compute in order to have the full power for your rendering.
Cycles can use your GPU CUDA cores to render, and is much faster than the CPU. Check out CUDA at wikipedia : http://en.wikipedia.org/wiki/CUDA
If you don't have a CUDA GPU, you can use Open Shading Language, but it's a little bit buggy and I couldn't recommended this method of rendering, for now. In the near future I have a feeling that it’s going to be much faster than the CUDA render procedure.
But enough with the technical stuff.
Let’s see another great thing about Cycles. Open the .blend file that we started last month, or just create a new one. Don't forget to check that the Cycles Render at the top is selected Also change one of your 3d view windows to show the rendered result.
Select the sphere, navigate to the Properties Panel and change the Surface shader from the default Diffuse BSDF to Emission.
You can check in the Preview window the cool effect that we create. You can adjust the Color and the Strength of the light that your object emits. Also for every shader you can adjust a lot of other things (as textures, for example) by pressing the little dot right next to color and strength values.
Select our metallic-looking cube, press the little dot next to color, and change its texture to Brick Texture. Check the result in your 3d view window and select different textures until you find something that you like.
TIP: The little dots are in every shader, not only emission, and I personally find them very useful to quickly create interesting stuff.
Another interesting shader is the Mix Shader. As you can easily understand from its name, this is a shader that you can use to mix other shaders. Two other shaders to be more precise. So, let’s select our cone and change the Diffuse BSDF shader to Mix Shader. Add a Glass shader and a Diffuse shader or a Glossy Shader and an Anisotropic Shader to our cone. Change the value of the Fac parameter to adjust the percentage of the second shader (0.000 means 0% while 1.000 means 100%)
Check the result on your preview window and adjust the settings as you like.
Another thing that I want to mention in this tiny little introduction on the Cycles Renderer, is the use of planes instead of lamps.
Most people working in Blender and Cycles use planes to illuminate their scenes. Looks like more “real world” lighting, and I have no reason to argue with them.
Below is where I am so far.
For this month, follow this link http://vimeo.com/68010380 to enjoy a wonderful work by 3 people and Blender (congratulations goes to Javier Trapiella, Baol Bardot Bulsara and Robert Green).
Also visit www.blendernews.org to enter and share with thousands of professional artists!
http://blendernews.org/xe/?mid=Feature_Articles&document_srl=1274