Apply OpenSubdiv Catmull-Clark smoothing.
- [Instructor] The Arnold attributes in an object shape node make it easy to apply subdivision surface smoothing at render time, and that's helpful in situations such as this where I've got a low level of detail table cloth that needs to be smoothed out. And the beauty of Arnold is that we can adaptively adjust the subdivision based upon the curvature or the edge length of the object. I've already got the Arnold render view open and the AI utility shader applied to the tablecloth and it's rendering in polygon wireframe mode.
Select the tablecloth, and let's open up its attributes with Control + A. And in the tablecloth shape mesh node, open the Arnold section. Scroll down a bit, and open the subdivision section. And it's turned off by default. The type is none. Let's see what we can do here. Set this to linear, and now it's just simply dividing each polygon into four polygons. And it's not performing any smoothing.
Set the type to catclark or catmull clark and now we've got the open subdiv algorithm. We can increase the number of iterations here to two, and now we've got much smaller polygons. We can optimize this and perhaps save memory at render time by playing around with the adaptive attributes down here. The adaptive error is the amount of optimization. As we increase this, we'll start to see the topology change in our wireframe rendering.
Let's set the adaptive error to 0.2. And then we have the adaptive space, and it's defaulted to raster. It's operating in camera space. We want this to actually work based upon the curvature of the surface, so change the adaptive space to object. And then we need to adjust our adaptive error a bit because now we've lost some of the detail. So bring adaptive error down to 0.15, and now especially in these corner areas, we've got enough detail.
Then finally we have the adaptive metric, and it's set to auto. It's got two options and it's supposed to automatically choose the best one for you. Edge length is not going to work for us because the edges here are all the same length. We just want flatness. And it doesn't actually change anything because the adaptive metric was very smart and it chose flatness for us automatically. And that's how to apply subdivison surface smoothing at render time using the Arnold shape node attributes.
And additionally, how to use the adaptive attributes to optimize the output of the algorithm to save memory.
- 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