Customize diffuse attributes of Arnold Standard material.
- [Instructor] In this chapter we'll look at materials and mapping using Arnold shading nodes. Primarily the Arnold Standard Surface material. It's an all purpose shader that replaces an older one from Arnold 4, which was called the AI standard material. The Standard Surface material is easier to use and a little bit more advanced. If you need to convert an old scene there's a utility for that in the Arnold menu under Utilities you'll see Convert Deprecated Shaders and this command will convert all of the Arnold 4 materials into Arnold 5 materials.
If you want to do that conversion one at a time you can do that through the Attribute Editor. Before we begin material editing I just want to talk a little bit about the test scene I have here. There are two soft lights at 45 degree angles to the camera and the material assigned to all objects in this scene is an ideal diffuse white. I've done this to isolate the material effects from any fancy lighting effects. So I've got a very simple soft light setup here.
Let's go ahead and assign a material to the flower petals. Go over to the camera view and select the petals, right-click and from the marking menu choose Assign New Material. The Assign New Material dialog opens. Go to the Arnold section and open up Shader, Surface, and choose aiStandardSurface. And the Attribute Editor opened automatically and we can set to work adjusting these attributes.
Let's rename the material shader, we'll call it petal_aiStandardSurface. Now let's open up the Hypershade from the status line, Hypershade. Hypershade opens with the Material Viewer and the Property Editor visible default. The Material Viewer is not really of very much use, because we can choose to render in Hardware, which will not look anything like the Arnold rendering, or we can choose to render in Arnold, but if we render in Arnold then we cannot render in the Arnold RenderView at the same time.
There's a limitation here. We can't use this mode of the Material Viewer and also the Arnold RenderView at the same time. I'm going to close the Material Viewer and do all of my testing in the actual scene using the Arnold RenderView. Close the Material Viewer. We've also go the Property Editor, which is just basically an edited version of the Attribute Editor. I'm going to close the Property Editor as well to give myself more space in the graph. But you can use the Property Editor if you want.
And now let's do that test rendering. Go up to Arnold, Render. The material's not very much to look at right now, it's just got default parameters. We've got the Base parameters here and this is the Diffuse Weight, increase that up to its maximum of 1. The Specular Weight is the shiny highlights. I want that to be turned off, so I'll turn the Specular Weight down to 0. Up here is Diffuse Roughness, that's going to add a little bit of surface roughness, which would look good with these petals.
We'll set that to a value of 0.1. Now we're ready to map some color onto the petals. We can go to the Color attribute and click Create Render Node. And from the Create Render Node dialog choose Ramp. What I'm going to do here is map a color through a ramp. And it's been graphed here, it's very small, so we can select those and press the f key to frame it. Here's the ramp.
We can select it and graph its network. And the ramp is feeding into the Base Color here. We can zoom in with the mouse wheel and pan around with alt and middle mouse button. The ramp will hold the colors, so let's go ahead and set those colors up. We can click here and that will select one of the flags on this ramp. Click on that color sample and let's set the Hue to 357, press Tab, and Saturation of 0.98, press Tab, then the Value of 1.
And we've now got a very bright pink color. Let's see what that looks like in the RenderView. Let's do another one over here. So click on the other flag, click on that color sample once again, and this time set the Value to 0.2 and the Saturation to .98 and Hue, once again, 357. Now we've got a very deep rich red color. And that looks pretty cool already, but we can now map this ramp with a file node.
So let's go over to the Create bin over here and you just want a 2D Texture, File, click to create that. And it comes with a place2dTexture node and we do need that, so let's keep that one. But we've also got another place2dTexture node over here connected to the ramp. What we want to do is to drive the Uv Coordinates of the ramp with the file. Let's delete this placement node that feeds into the ramp, just select place2dTexture1 and press Delete on the keyboard.
And set this up so that we can connect the file's green Out Color channel to the V coordinate of the ramp. If we select the ramp we're in V Ramp mode. Open up the Uv Coord, over here open up Out Color, and connect Out Color G to V Coord. That's been connected and now we can assign the file. Select the file node and go over to the Image and click browse and in the current project sourceimages we'll see whitePetal.png and it's a black and white image that was originally from the paint effects brush that I modified for the flowers.
Click Open. And if we zoom in here a little bit with the wheel we can see there's a pattern here on that sample and in our Arnold RenderView we'll also see some mapping here. So we, again, zoom in there as well, we can use the wheel to zoom in in 2D. If we want to actually get closer to the flowers we can dolly forward in 3D. Go to the Arnold RenderView menu and choose Window, 3D Manipulation.
And now we can use the mouse wheel or the Alt + right mouse button keyboard combination to dolly forward and back. And we can track in the view using Alt and middle mouse button. As that rendering fills in we can start to see the texture and if we want to edit that, of course, we can go back to the ramp node and adjust the positions of these color samples, or flags, or change their colors. So let's maybe reverse this, see what that looks like.
To finish this we can add some Subsurface Scattering, which is light bouncing around inside the object itself. Go over to the Material node and select it, and we've got a Subsurface section here with a Weight parameter. We can increase that and things will start to go white, because the color is defaulted to white. Let's connect the ramp to the Subsurface Color. Dolly back a little bit with Alt and right mouse button.
Out Color to Subsurface Color. Now that's connected. We can play around with the Weight. With Subsurface turned off, with a Weight of 0, the Diffuse Color will have full influence. As we increase the Subsurface amount we'll see the Diffuse or Base Color lose influence and we'll see more of whatever color we have here. In this case we also want to enable an option for thin wall geometry.
Scroll down a little bit to Geometry and turn on Thin Walled. And this will now give a good simulation of a thin petal. Let's set our Subsurface Weight to 0.3 and that's how to set up the basic parameters and map the Diffuse Color for an aiStandardSurface material.
- Arnold rendering concepts
- Lighting with Maya and Arnold lights
- Controlling exposure
- Filtering light with Gobo
- Light attenuation with Decay
- Image-based lighting with Skydome
- Exterior daylight with Physical Sky
- Arnold Standard Surface 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