Learn how to control advanced transparency effects.
- [Instructor] Let's apply transparency and refraction to this vase and the water within it. Before we do that, we need to make sure that they are not opaque, and that is the default state of objects. They're considered to be opaque by Arnold unless we turn opacity off. Select the vase, and go into its Attributes, Control A. And in its Mesh Shape node, open up the Arnold section, and disable Opaque. The same goes for the water that's inside the vase.
Open up the Outliner, and at the bottom we have vaseWater. Select it, and in its Attributes, also turn the Opaque flag off. We also need to make sure that we have enough refraction rays, so that light will be able to pass through all of these surfaces. Open up the Render Settings, and in the Arnold Renderer tab, open up Ray Depth, set the number of refraction rays to 12, and to make sure that all of those rays actually get calculated, set the total number of rays to 20.
Close the Render Settings window, and let's assign a new material. Select the vaseEdited, right-click in the view, and choose Assign New Material. From the Assign New Material dialogue, choose Arnold Shader, and click aiStandard. In the Attribute Editor, let's rename this new material. We'll call it vase_aiStandard. In the beginning of this course, I strongly recommended all viewers to update Arnold to the latest version, and if you've done that, you'll have access to the presets for the aiStandard node.
In the Attribute Editor, the presets button has a little star, or asterisk, next to it, indicating that presets exist for the current node type. Click and hold that Presets button, and choose ai_Glass, Replace, and that sets up most of the basic attributes for glass. The Diffuse Weight is 0, the Specular Weight is 1, and the Refraction Weight is also 1, down here.
The Index of Refraction is set to 1.5, which is the correct density for glass. Below that is the Dispersion Abbe Number, and that allows Arnold to calculate chromatic abberation, or rainbows. And the Abbe Number is a little bit backwards, as you increase the Abbe Number, the amount of dispersion actually decreases, and the rainbow effect will be constrained to a smaller area on the screen. As you reduce this number, the rainbows become larger.
Let's split the difference here, and set the Abbe Number to 50. That's a pretty good setup for glass. Let's duplicate that and make some changes for water. I'll close the Attribute Editor, and open up the Hypershade. Scroll down in the materials, and we're looking for our vase_aiStandard that we previously created. Select it, and then graph its network by clicking input and output connections. Here's the aiStandard vase glass material, let's make a duplicate.
Select that node, go into the Hypershade menu and choose Edit, Duplicate, Without Network, and select the duplicate and then rename that one. So this is not going to be the vase, this will be water, so let's rename it water_aiStandard. Just a couple of changes here, if we scroll down in the Property Editor, we can adjust the Refractive Index. Set that to 1.333 for water.
Also the transmittance, water allows more light to pass through than glass does. Click on the Transmittance color swatch, and set the value to 0.98, and press Enter. And that allows more light to pass through the water. Last, we just need to assign the new water material to the water object. We've got the Outliner open here. Select vaseWater, right-click at the top of the node, and from the Marking menu, choose Assign Material to Viewport Selection.
With that assignment made, we can close the Hypershade, and open up the Arnold Render View, and you want to render camera 2, and we see we've got a nice glass and water effect there. And that's how to set up refractive materials in Arnold.
- Arnold rendering concepts
- Lighting with Maya and Arnold lights
- Controlling exposure
- Filtering light with Barndoor and Gobo
- Light attenuation with decay
- Image-based lighting with SkyDome
- Exterior daylight with Physical Sky
- Arnold standard material attributes
- Mapping material attributes
- Rendering refractions
- Mesh subdivision and displacement at render time
- Shading effects such as ambient occlusion and vertex color
- Camera effects such as fisheye and depth of field
- Animation image sequence rendering