This tutorial leads you through a simple example of how to render a scene in Maya using Arnold.
It assumes you have already:
- Installed Arnold for Maya.
- Set up licensing (if you don't want watermarks in your renders).
- Loaded the plug-in.
1. Start Maya.
2. The first step is to tell Maya to use Arnold as the current renderer. In the Render Settings dialog (from the top menu bar, Window > Rendering Editors > Render Settings, or by clicking), set Arnold Renderer from the "Render Using" 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).
- Next, create a plane to act as a floor. Click on the Polygons tab of the Maya Shelf, and select the icon for Polygon Plane icon from the icons shown below (a flat plane). Click to place the corner of the plane and drag to size the plane.
- Select the floor plane and then examine the attribute editor (ctrl-A will display the attribute editor if necessary). By default the Maya ‘Lambert’ material is assigned. Select the lambert1 tab and then click on the 'Color' attribute (under 'Common Material Attributes') and choose a more interesting color than the default gray (let's choose blue for this example).
- Next, create a sphere, again by choosing from the Polygons tab of the Maya shelf, and place it on the floor plane. By default the sphere will intersect the floor plane in the y-axis (this will be obvious in shaded view, which you can switch to by pressing the '5' key while in the main view). This is fine for now, leave it where it is.
- For this object, let's assign a new material instead of the default. Select the sphere, and hold the right mouse button down until the shortcut menu appears, and select 'Assign New Material' from the shortcut menu.
- This brings up the following menu from which you can select what material you want. Note that Arnold built-in materials all have the prefix ‘Ai’. Choose an ‘AiStandard’ material.
- Now if you look at the attribute editor while the sphere is selected you will see the attributes of the AiStandard shader. These attributes are discussed in more detail here. For now, just select a green color for the Diffuse Color.
- Next we'll create another object… let's choose a cylinder this time. Place it in the scene, select it and bring up the 'Assign New Material' menu from the right-click shortcut menu as before.
- Assign another new AiStandard material. This time, set the diffuse color to red. You should now have a scene that looks something like this.
- Now we’re ready to open the Render View window (Windows > Rendering Editors > Render View or clicking on the . icon)
- Start an interactive render by clicking on the IPR clapperboard icon .
…and the render is black. Don't panic! We just need to add some lights.
- We can choose from the Maya standard set of lights. Create a point light (select the Rendering tab on the Maya shelf and Point light from the selection of lights shown underneath).
- By default the point light will be located at the origin of the scene, and if you still have the IPR window open, and depending on where you placed the other objects, straight away you should see that some color bleeding is visible.
You may need to move the light to see the shadow better.
- 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 Maya, where lights are by default set to have no decay. In fact, the decay setting for the light under the Point Light Attributes section of the light's Attribute Editor will have no effect, since this is a Maya control. To change the decay in Arnold renders you will need to scroll down to the Arnold section of attributes.
Point light's Arnold attributes
The above dialog illustrates this point. The Decay Rate shown under the Maya settings (Point Light Attributes) is set to No Decay (the Maya default), but this only applies to Maya renders, not to Arnold. Further down the dialog, under the Arnold settings you can see the Arnold default for Decay Type is Quadratic.
You can also address the 'too dark' issue by either altering the intensity of the light, or changing the Exposure attribute. Generally speaking we recommend you work using the quadratic decay as it is more realistic, so you should choose intensities (and the scale of the model) accordingly, and then use the exposure setting to fine tune.
- If you increase the radius of the light (select the point light, go to the Attribute Editor, expand the Arnold tab, and alter the Radius) you get soft shadows.
- Let’s make the sphere more Specular, to get reflections. Select the sphere, bring up the Attribute Editor, open the Specular group of the AiStandard attributes and change the Weight (specular weight) attribute to 0.3.
- Specular roughness needs to be zero for mirror reflections. Alter the Roughness attribute in the same area and enter a value of 0.0.
The result of all these changes is available instantly in the IPR window, so you work interactively changing materials and lighting without having to re-render to see the effect of your changes (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.