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In this movie, we're going to create ambient occlusion as a separate pass. And we're going to do it through a manual process. And it might seem a bit roundabout. But there's a method to my madness here. There are some pretty deep issues with the way that mental ray in 3ds Max deals with ambient occlusion. As you know, we can output ambient occlusion directly from. The material, arch and design, but, unfortunately, we can't control some of the key parameters like spread and falloff.
If you want to have control over those parameters, then we have to use the separate ambient reflective occlusion node, as we did. And theoretically, we should be able to render that out as a separate render element, because, there's a render element called Shader element, that lets us choose any node in the tree, and output that separately. And that should work, but, unfortunately, it treats the entire scene like an environment, and it's almost impossible to exclude objects. There's a method where you're supposed to be able to exclude them, but it doesn't actually really work the way you need it to.
So, what we want in this case is to have ambient occlusion only on the watch face, and we want that to be affected by nearby objects. But we don't want those nearby objects to be affected by it. So, in order to do this, we're going to create shaders. One with ambient occlusion, and one with no ambient occlusion. And they'll be self-illuminated with no lighting, no exposure control, no final gather. And none of the bells and whistles. No render elements, and nothing. And doing it this way, is going to take a little bit of setup.
But it's going to render much faster, and we will actually be able to control the process, which of course is very important. All right, so the first thing we'll do is turn off all the lights, go into Tools> Light Lister, and switch all of those lights off. Then we'll want to go and turn off our exposure control under Rendering> Exposure Control. And just make it inactive by switching it off. Now, we need to hide some of our objects. So, we'll go into the Manage Layers dialogue, and hide the Glass layer.
Also hide the Hands and Markers, because, those are not significant to the ambient occlusion. Now, we'll go into the Material Editor. And we want to create a new material. Just a standard one. We don't need any fancy arch and design. Let's get this out of the way. Just a standard 3ds Max material. Here it is, standard. Just drag that over. Double-click on it, and we'll call it AO Self Illume. We can set the diffuse amount to black. It's actually not going to render, just set that down.
Turn the self-illumination color switch on. Which means that the self-illumination will be driven by a external map, and that will be our ambient occlusion node that we created before. So we're going to make that connection. So we'll, take this ambient occlusion node and connect it to self-illumination. And you can see we have a little m there now. Now double-click on that ambient occlusion node, and set its bright color to white. Absolute white. Now we built that material, and we want to assign it to the watch body.
So, select that layer, and then click to select the objects in the layer. Double-click the shader, the material here. And then assign it. And those objects turn black. So you've done that one. Now, we also need to make a material that does not have ambient occlusion. So, let's duplicate this one. Hold down Shift and drag to make it duplicate. And break this connection, to the second one. Delete that. Double-click on this, and we'll call it, self illum. And we want its self-illumination to be white.
So we can click on that, and set that to be 100% white. 255. And we want to assign that to the back, and the wristband, so select the back, Ctrl+Select the wristband layers, then select the highlighted objects, and then with this material, selected In the material editor, assign material to selection. Okay, so we've made one material that has ambient occlusion, and assigned that to the watch face objects, and another one that has no ambient occlusion, but is fully self-illuminated.
And assign that to all the other visible objects. Okay, cool. Now we're ready to go into our render setup. And we want to do a lot of stuff in here. First of all, in Global Illumination, we want to turn off Final Gather. Then we want to go into our Render Elements and turn all of these off, because we don't want to re-render these. So we Shift+Select all of those, and turn off the Enable switch, and they'll all get turned off. Then in the Comment tab, we're not going to render out to a file through this method. We're just going to do it interactively. So we'll turn off Save File. Okay, and then do the rendering.
Okay, that looks pretty good. That's exactly the result that we need, which is that the watch face objects are all being affected by each other, and also by nearby objects. But, the nearby objects are not being affected at all. We don't need to apply ambient occlusion to the wrist band or any of this other stuff. We're now we're ready to store this image on disk. Click on the Save Image button, and we'll save this as studio_lighting_AO. And when we click Save, we should get the dialog that asks us what options we want for opening XR.
And in this case, we want the type to be RGB. We don't want to store the alpha channel in this case. That would just complicate things. So we're going to have no alpha channel in this. Click OK. That was a bit of an involved process. We had to create special custom shaders. We had to turn off all bells and whistles, but this is the only way we can control ambient occlusion. In order to mask objects, in order to make sure that we can control all the parameters, like the spread and the falloff.
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