Join Adam Crespi for an in-depth discussion in this video Add ambient occlusion and metalness, part of Substance Designer for Architectural Visualization.
- [Instructor] When you're working in a physically-based rendering workflow it's important to use all of the different properties of that particular material to really bring out the nuance and subtly in it. So far we have an Albedo, a normal, and a roughness and we have a varied tile with a really great scatter of light across the surface. I'll take another look at that reference image and see what else I need to add in here. What we can see with all of these products, and I'll look again at the Tropical Thunder, is that there's a certain metallic quality to some of the tiles.
Their color definitely varies and we can add in more variation to the color if we need. But some of the tiles are a little more metallic looking. What I need to do then is to add in a metallic quality and then some ambient occlusion. Ambient occlusion on the tiles is not necessarily going to darken them, but instead will let the indirect lighting show more across certain areas of the tiles when it's in indirect or bounced light. I'll go back to Substance Designer and get the metallic part working. I'm back here in Substance Designer and we can see I've got two slots left to use here in those material outputs.
I'll select them and press f to frame in. We have Metallic and this controls the metalness of that surface, how much like a metal does it appear? And also, does the specular highlight start to approach the Albedo while the actual color goes towards black? Or does it read as a surface color, like we have? We have a height, which really aids in the appearance of that tile having some relief. If you've worked in parallax mapping that's where we'll use this. I need to add in an Ambient Occlusion and then get the Metallic and Ambient Occlusion properties going.
I'll press the spacebar and add in another Output. Clicking on Output and naming this Output Ambient Occlusion. Ambient Occlusion is the blocking of bounced light by the adjacent surfaces. And what it means in this workflow is really where that indirect or bounced light will show more in non-direct lit surfaces. It's not necessarily going to lay over that traditional black ambient occlusion in the grout that we've often seen in renderings. I'll add in a Usage, clicking on the plus next to Add Item, and dropping down under diffuse to choose ambientOcclusion.
Typically this is a grayscale and you can choose in this Usage to use one of your channels or leave it as RGBA. Depending on where you're going with this substance your application may knock out the unused channels. Now add in the Ambient Occlusion and the Metallic part of this tile. For the Occlusion we can generate it very easily from one of our existing bricks. I'll take a look at the different brinks I have blended and see what's suitable for Occlusion.
This one, which generates our roughness, has too much variety to it. What we need is actually a more consistent height map for the Occlusion with just a little bit of variation. The map we've used to generate the normal is much more suited, where we've got darker lines in the grout and generally lighter tile with some variation across it. I'll add in an Ambient Occlusion node, pressing the spacebar, and in the search bar typing A-M-B, or A-M, and there's Ambient Occlusion.
This node then takes in a height, as it says, and outputs an Ambient Occlusion. What I'm also going to do is add in some Levels. I use Levels a lot, as these let me really calibrate where does that value sit incoming. Now as you notice I had Ambient Occlusion selected when I clicked Levels, so I got the Levels at output. I'll break that connection, as it's in the wrong place, by selecting that connection line and pressing Delete. Then I'll move the Levels to the other side and pipe that Blended output in.
Then this Levels will connect to the Ambient Occlusion and I'll double-click on the Ambient Occlusion to refresh that thumbnail. Then I'll hook up the Ambient Occlusion into the Ambient Occlusion output. What we're seeing here in the Ambient Occlusion down in the bottom right of my screen is that the height map, the grayscale, has generated Ambient Occlusion in that grout with a little bit of darkening across some of the tile surfaces. I'll click on that Ambient Occlusion and we can see here we've got Low, Middle, and High frequencies and also Spreading.
Spreading then controls how that Ambient Occlusion spreads across the surface. Even cranking up Spreading to 1 doesn't give me too much Occlusion, as that relief is simply all in the grout. I'll leave it fairly low and we can play with things like Middle frequencies if we need. Where does the Occlusion occur more or less? Pulling it down then gives us really odd haloing in that tile. What I'll do is to leave it alone and pull up my Levels just a bit. Bringing up the Low and Mid Levels to get a little more darkness going, but pulling back the High to get some of the Occlusion off the surface of that tile.
Then I'll adjust those Levels. I had put a Levels node in and not used it yet. I'm going to leave the Ambient Occlusion selected and showing while I select the Levels node. I'll zoom in on those Levels, and in the Levels I'm going to brighten up those tiles. Swinging this top middle node to the right then gives me more darkness across the surface, pulling it to the left takes out some of the relief. So in general they're nice and bright with just subtle variation. I want my Ambient Occlusion really to cluster tightly in that grout.
Where we can really see this going on is on the underside of the tile. There's just a little bit of extra bounced light in the grout, a little bit of glimmer across it in the ambiently lit situation. Ambient Occlusion is pretty straightforward, it just adds a little extra depth to that material. We just need a grayscale to generate it and then probably some Levels and an Ambient Occlusion node. Now look at the metalness and my tile will almost be done. For metalness I'm going to use one of the same Blend nodes I've got.
I have a Blend here and this one is controlling the roughness. If I take this Blend and straight pipe it into the Metallic I'll get some interesting looking tile. There's definitely a variation across and some metallic qualities to them. This roughness map, this grayscale Blend is great for that Metallic map, as I want some of the same tiles that are either smoother to be a little bit more metallic and have the extra little shine to them. I'll make sure that nothing is selected and click Levels to introduce a Levels node without directly connecting it to anything.
Now connect the output from the grayscale that's giving me my roughness to the Levels and then Levels to that Metallic. With the Levels selected I'll start to play with the output. Saying, in this case, where is it more or less metallic? I'll pull down the bottom right white key, so in general this image gets darker. It's a little bit less metallic. Then I'll take that middle range and slide it around, so that I get a little bit overall more metallic in there, possibly adjusting just a bit.
And then bring back a little bit of the contrast in here. Now the one downside to using this is that this is going to say that my grout is actually quite metallic. Where it is lighter in the grayscale it is a more metallic surface and I don't want to use metallic grout, I want possibly slightly metallic tile. What I need to do then is to blend over a dark grout. Thankfully I already have one here. Down at the bottom I have a Brick Generator and this Brick Generator gave me white bricks on dark grout.
I'll put in a Blend, connect that white brick with a dark grout to it, and then pull this Blend up where that Metallic node is. There's the Levels that are going into my Metallic and I'll take the output from here instead into the background. And then from that Blend into the Metallic node.
Temporarily we can see all of my tiles get very metallic in here, which could be a nice look if we want metallic tile. What I need to do though is simply darken that grout. What I'm going to do is double-click on that Blend node and change the Blending Mode to Multiply. In Multiply white is like multiplying by one. We're taking the over color times the under color and dividing by the color space. Multiply is always a darker result, so multiplying by black really blacks out the grout, multiplying by white is like multiplying by one, so the gray is preserved.
And now I have varying gray, slightly metallic tiles over exactly not metallic grout. In this case, because I have no Alpha going I'm going to take this Alpha and say Ignore the Alpha. If you have a chance to optimize your substance you should. Anywhere you can tell it to ignore an alpha is good, because that saves time in calculation. Now I've got tile that is occasionally metallic, has a good variation across the color, has a varying roughness, and some Ambient Occlusion to really let a little bit of that indirect light show a little more in the grout depending on the situation.
My tiles have definite variation and a good incidence of the different colors in here. If you'd like you can continue to adjust the color and even look at blending in additional colors, so that the colors of the tile are not nearly as uniform. We have the base setup ready for the tile, so that we can continue to add variation and to have as much tile as we need for our large applied surfaces.
- Mosaic and metallic tiles
- Determining tile patterns
- Varying tile roughness
- Exposing parameters for design flexibility
- Testing tiles in a scene
- Crafting subtle metallic properties
- Patterned tile for accents
- Wood tile flooring
- Creating wood grain from noise
- Ashlar veneer
- Molded wall panels
- Woven mesh