Join Craig Barr for an in-depth discussion in this video Ambient occlusion, part of Mudbox 2016 Essential Training.
- So, as you can see, we've taken this creature here to a bunch of different levels in detail. We've sculpted in pores, and scales, and of course, on the helmet, it has some damage effects going on the steel, and we have some woodgrain happening on the helmet as well. We want to take a look at how we can extract an ambient occlusion map, and also a cavity map to use either in our texture painting workflow, or for within our rendering pipeline. Let's take a look at how we can do that here on the helmet. So, I'm going to right click and select the model of the helmet.
Going to go into the upper-left corner, UVs & Maps, then we go down to Extract Texture Maps, then I'm going to create a whole new operation. Now, down here, we have a bunch of different options. We're only concerned with Ambient Occlusion Map, so we'll click that. What we going to see here is it's going to give us a little bit of an overview as to what's about to happen, and a thumbnail as the result we're going to get. An ambient occlusion map is basically going to produce a map as to areas of where objects are occluded from light. So we want to get that kind of nice, subtle, shadowy effect that's happening in the little crevices or the edges of the creases on this helmet.
So, what we're going to do now is define the target model, and that's our base mesh. By default, Mudbox is going to recognize that the lowest resolution, base level of this mesh, is level 0. So, we've defined our target. The source model is always going to be your highest resolution, where all the details live, and that's going to be our highest level at level 5. And that's our sculpt, our highest level sculpting where we've sculpted all those details in. So now we've defined our source, and we've defined our target, we can now go down to how we output that map.
So, we can define the quality, and you can see there's a couple of different settings in there, from Fastest up to Best. Obviously, Best being your highest quality that you're going to get as a result from that quality setting. Method, you have two Method choices here, Ray Casting and Subdivision. Ray Casting is if you're using two different meshes. And example of that would be if I had a retopology of this helmet, I could could use this high-resolution sculpt mesh to base my ambient occlusion on to the lower resolution retopology mesh. In this case, we're using the same model, I can use Subdivision, I can click that.
So now we'll just scroll down here to the bottom to look at the image properties that we want to set. Here by default, the image size will be 1K, and see, we can go all the way up to 32K if we'd wanted to. Let's just leave it at 1K for this example. Now, the default settings for ambient occlusion produce pretty decent results. You can see that we have the default filter, Shadow Contrast and Shadow Darkness, let's just leave that, and I'm going to show you the results that we would produce. Down here, we would define the type base file name and the type of texture we want. We can define the bits per channel, from 8-Bit, all the way up to 32-Bit floating point, and we can define a couple of different image formats, from PNG, JPG, all the way through, TIFF, and even a Photoshop document if you wanted to.
Now, I'm going to take a look, for the interest of time, these maps don't take too long to write out, but they can take a few minutes, so in the interest of time, let's just close this window, and take a look at some results. Now, I have one here in my Diffuse paint layers, so I just turn that one on. You're going to see that we just essentially get this white and black map. And if we zoom in, or frame that, what this white and black map is, it represents all the different ambient occlusion. And I should actually turn off any filters associated with the viewport filters that I had turned on, and the ambient occlusion map is just going to give us this black and white map, but you can see we get these kind of shadowy effects along the edges.
And this really helps, especially in a texture painting workflow, or if you wanted to have it as a separate map into a shader network, for example, in Maya. So that's how you write out ambient occlusion map. Now, let's take a look at something different here, using the same technique, but dialing in some of the filter attributes to get a more fine, or tight result here with more detail, and that is a cavity map. And you can do that in Mudbox, you just have to know how to dial in the filter settings for this. So, I have one here, if you want to take a look at what I've done. All it is, is the exact same thing we were using, the ambient occlusion map.
The only difference is, this is one I've used for the horns here, the same idea. The only difference that I've set here is this filter. So, the filter by default will be set to .01. I've padded this with three extra zeros in the front, all the way down to .0005. Now, why did I do that? That's going to give me super fine detail. It's going to get into all those woodgrain. The things that this regular ambient occlusion map that I've just generated are not. Cavity maps are going to get into all those cavities, all those little dings and scratches here, and it's going to give me all of that fine detail in a black and white map.
And we can take a look at the preview of that with our helmet, let's turn off that AO map, and go down here, and if you have access to the exercise files, you'll see that I have all the chapters here grouped here, chapter 10, chapter 13. And here's the helmet cavity map. So, we'll just turn that one on, and you can see the difference, right? You can see all those details are showing up now, through the grains, here's the little nicks and scratches where we're getting all of that detail, cavity map, developed here for a use into a texture painting workflow, or again, for like something like a shading network maybe, for example, in Maya.
So, there's a quick overview as to how to extract and ambient occlusion map, as well as a cavity map, for use in your production workflow.
Craig Barr also covers retopology, posing, and rendering and exporting, providing a complete learning experience on Mudbox workflows typical in feature film, game, and character design projects.
- Getting around Mudbox
- Creating primitives
- Importing models
- Working with layers
- Painting with stamps and stencils
- Retopologizing models
- Extracting detail maps
- Texture painting
- Rendering and exporting