This topic leads you through a simple example of how to render a scene in CINEMA 4D using Arnold.
It assumes you have already:
1. Start CINEMA 4D.
2. The first step is to tell CINEMA 4D to use Arnold as the current renderer. In the Render Settings dialog (from the top menu bar or by clicking), set Arnold Renderer from the Renderer drop down menu.
Note how the renderer options are organized in groups (this is discussed further in sub-topics of the Arnold Render Settings topic).
3. Next, create a plane to act as a floor. Select the icon for Plane from the icons shown below (a flat plane) or from the menu, select Create > Object > Plane. Scale up the plane to at least twice its original size.
4. By default the floor plane has no material assigned and renders with a default lambert shader. Assign a standard_surface shader instead. In the Material Manager, create an Arnold 'standard_surface' shader by selecting Create > Arnold > Surface > standard_surface.
5. Select the shader and in the Attribute Manager change the Base color to mid grey via the color picker (click on the Color swatch first). Drag the material from the Material Manager onto the plane in the perspective view.
In Arnold you can connect shaders together resulting in a shader network. When you create the shader from the menu, an Arnold Shader Network Material is added to the scene with which you can build a more complex network.
6. Next, create a sphere - Create > Object > Sphere. By default the sphere will intersect the floor plane in the y-axis (this will be obvious in the Gouraud Shading option from the View > Display menu. Move it up in the y-axis so that it rests on the plane.
7. For this object, we can assign a new material instead of the default. Select the grey standard_surface shader in the Material Manager and press Ctrl+C and then Ctrl+V to paste a duplicated standard_surface shader. Change the Base color to a green color as we did for the plane. Drag the material from the Material Manager onto the sphere in the perspective view.
8. Next we'll create another object… let's choose a cylinder this time. Position it in the scene above the floor plane.
9. Assign another standard_surface shader. This time, set the Base color to red. You should now have a scene that looks something like this.
10. Now we’re ready to open the Render View window (Plugins > C4DtoA > IPR Window). Note that the interactive render is automatically started which is shown by the Play icon.
…and the render is black. Don't panic. We just need to add some lights.
11. We can choose a light from the CINEMA 4D standard set of lights. Create a default omni light (select the light bulb icon on the CINEMA 4D shelf and select the light bulb icon from the selection of lights shown underneath).
12. Select the light and enable shadows from the Shadow menu. It makes no difference if you select 'soft' or 'hard' shadows, Arnold will automatically raytrace shadows from the light.
13. By default the omni light will be located at the origin of the scene. Position it to have a nice look.
14. You may still find that the scene is a little dark for your taste. It's worth mentioning at this point that lights in Arnold use quadratic decay by default (because that is what happens in the real world, and Arnold is designed to work with a physically accurate approach to modeling and lighting). This is different to the default behavior in CINEMA 4D, where lights are by default set to have no decay. In order to change the light attributes in Arnold renders you will need to add an Arnold tag to the light.
You can also address the 'too dark' issue by either altering the intensity of the light, or changing the exposure setting.
15. If you increase the Radius of the light (select the Arnold tag, go to the Attribute Manager and alter the Radius under the Main tab) you will get soft shadows.
16. Let’s make the sphere less specular, to get less reflections. Select the material assigned to the Sphere, bring up the Attribute Manager, open the Specular group and change the Weight attribute to 0.3. Increasing the Specular roughness value will blur the glossy reflection of the scene, making the light source more visible. Increase it to around 0.25.
The result of all these changes is available instantly in the IPR window. This means you can work interactively by changing materials and lighting without having to re-render to see the effect (simply wait slightly longer for a better quality render if you've got things set up correctly).
That's the end of this short introductory tutorial. Now that you know how to assign and edit Arnold shaders, and alter Arnold settings of lights, it might be useful to play around with various settings for a few minutes before reading on.