Increase render samples for Skydome interiors.
- [Instructor] When the render completes in the Arnold render view, we can see that it's very grainy. The lighting is what we want, but the sampling is nowhere near high enough quality. Let's open up the render settings. In the Arnold renderer tab, we have the sampling section. I've already set the ray depth. Let's open that up and take a look. I've got five diffuse rays to provide sufficient bounce light, four specular rays to prevent any black areas on shiny surfaces near one another, and transmission set to eight by default to permit rays to travel through transmissive materials.
Up in the sampling, let's start increasing these values. Bring the camera rays up to seven and that's going to drastically increase the number of samples here. If we set the camera rays back to three, which is the default, we see we have a minimum of 117 and a maximum of 243. If we increase the camera anti-aliasing to seven, now our maximum is 1323, so it's jumped up quite a lot.
We can also increase the rest of these individually. Bring the diffuse samples up to eight. We really need to increase that quite a lot to remove the grain on the walls and other diffuse surfaces. Then the specular samples, increase that to four to improve the quality of shiny surfaces, and the transmission or refraction we'll set to a value of three. Sub-surface scattering is not very important in here, although I do have some sub-surface scattering on the petals and leaves.
Those are not in closeup or anything, so we can leave that at the value of two. Now let's look at our number of samples up here. Our maximum number of samples has increased from 250 to over 5,000 samples. This is about 20 times the number of samples that we saw a moment ago with default settings. We can be certain that our render times will increase by at least an order of magnitude. If we needed to bring render times down, then we could design a studio lighting setup as we saw in the previous chapter.
As you see the progressive refinement in the Arnold render view, you may see some fireflies, little bright spots there. As the rendering completes, those will probably go away. And the reason for that is that they are controlled through this clamping section here. Open that up, and what it does is prevent those fireflies. And when that's on, you have a value that you can adjust to set a threshold for the clamping of the fireflies. As you adjust these parameters, you really don't want to wait for the entire render.
So one last reminder, use the crop region mode. Enable that, and then select an area on the screen, and only that area is going to render. You might want to display your CPU usage while you do this, so you'll know when it's actually finished, because currently, it's actually still rendering. Ah, there, it's just finished now. So that's the quality we're going to get, and we can zoom in, of course, with the mouse wheel and position the frame with ALT + middle mouse button. We can also move the region around and resize it.
We can click in the cross in the center and position that somewhere else. We can drag the rectangle in order to resize it. And just do that all over in different representative areas of the frame while you adjust the sample values so that you don't have to wait for the entire render. Here's a finished rendering with these settings at full screen, and of course, that took quite a lot longer to render. But that's how to use the skydome for interior day lighting. And that concludes our chapter on natural and environmental lighting.
- 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