Layer light and shader AOVs, and adjust lighting.
- [Instructor] Picking up from the previous movie, we just rendered out a series of EXR documents using Arnold's AOV render passes feature, and let's just stack them together in Photoshop. Go to the File menu, and choose Scripts > Load Files into Stack. And in the Load Layers dialog, click the Browse button. And you'll need to navigate for your AOV images, and I've got them here in my current project.
Exercise Files > Images > AOV, and then these are the five EXR documents inside their own respective folders. Now the order that we load these into Photoshop will determine their initial layer order. The first one we load will be the top layer, and images that we select subsequent to that will be below it in the layer stack. We want the beauty pass to be on top.
Choose beauty, and then select the EXR document, and click OK. Then we need to go back into the Browse dialog, and select the next one which would be listed below it in the layer stack, and ironically I want the backdrop to be pretty high in the stack. So select backdrop, and then click the file name, and Open. Browse once again, and this time we want to go for the key light, so select key, and select the image, and click Open.
Browse again, choose the fill light and its file. And then one more time, finally, the back light and its file. So we loaded all of those files into the Load Layers dialog here, and we don't want to align them or anything like that. Just click OK. The layers have all loaded in, so let's rename them. So double-click on the top layer and call it beauty.
The next one down is backdrop. Then we got the key light. Then the fill light. And finally at the bottom is the back light. So if we turn off visibility for the beauty pass, then we'll see the backdrop composited over the key light. So the backdrop is on top here. So let's leave the backdrop alone; it looks fine. The key, fill, and back needed to be added together.
So let's select the key layer, and set its blending mode up here to Linear Dodge > Add. And now, key and fill are adding together. And let's select the fill layer, and also set its blending mode to Linear Dodge > Add. And now key, fill, and back are all adding together, and then the backdrop of composited on top of that. If we toggle the visibility of beauty, we actually don't see any difference here.
So adding these lights together is the same as rendering all in one pass. All right, I'll turn the beauty visibility off, and now we can adjust our lighting by making changes to these various layers. For example, we could apply an exposure adjustment layer to brighten or darken one of the individual layers here, or we could just do the simple thing which is to play with the opacity, and that'll just give us the ability to dim down the various lights.
So I can select the key light, and then click on its opacity and bring that down, and it's just like I had re-rendered my image with a dimmer key light. All right, I'll bring that opacity back up. If I wanted less fill light, I could bring its opacity down. Okay, that's how we can use a compositing application such as Photoshop to stack together the various AOVs and actually change the lighting of the shot after the render is completed.
- 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