Join Donovan Keith for an in-depth discussion in this video Adding mildew to the ceramic tile's surface, part of Cinema 4D: Creating Materials.
In this video, we're going to tackle adding mildew to a grout surface. This is our image without any soap scum or mildew. This is it with the addition of some soap scum which you can view in a different video. And this is more or less the final result that we're shooting for. So let's talk about mildew and what it's like. Now with mildew like all materials, first we want to try and find some reference imagery which I've done. And then we want to talk about the color, the specularity, the bump and maybe the diffusion of that material.
So looking at this mildew right here, I can get a sense of how it's placed, but it's a little difficult to make out the color. In this example, I'm seeing the mildew a little bit more up close and it appears to have a fairly high diffusion levels. So it's darkening the surface that it's on pretty strongly. The bump seems to be coming from the surface below it, the surface of the grout. And the color seems to be a little red brown if it is anything at all. Now, let's see if we can find a better example of this and unfortunately we got exactly what we were looking for. This is a rust and mildew build up.
Mildew, I believe is a sort of mold that forms between the tiles in your shower, and that's why it shows up in these big clumps and sort of grows out with these organic borders. So, in terms of color, we're looking for something that is sort of black and, rusty brown, maybe a dark green. If it's wet, it has a fairly high specularity, and if it's wet, it also is fairly high in diffusion. The bump for the surface is coming sort of from the grout below and ugh, that's just disgusting. Now, onto an image that we're going to use to try and superimpose our mildew on our surface.
This is a yellow image map that I've downloaded and it's just a water color and I've converted this into a seamless alpha channel that looks like this. And I've chosen this because it adds semi-organic borders and well also I already had it. So well ideally I would to use a black and white alpha from say moss growing or something that's going to have those truly organic borders. This is going to have to do because well, it's what I have. So let's go ahead and open up our starting scene. And what we'll see is this, it's our tiles with a little bit of soap scum on top.
Now, in order to create our mildew, we have a couple of options. One, we could add it to our existing grout texture. But I don't like that because it makes it more difficult to scale my texture for my mildew after the fact. So I'm going to build it separately. And to do that, I'm going to create a new material, which I'm going to name Mildew. Now, if we'll recall, the color of mildew is sort of rusty green-brown. So, I'm going to go into my color channel, and I'm going to find a green-brown, fairly dark one, maybe kind of saturated like this.
And chose Ok. So for me that's a value of 79 59 22. Specular, I'm going to keep fairly low. I'm going to assume that we're working with mildew that is already dried. We're not in a wet shower here. So, I'm going to lower the height, maybe lower the width a little bit and the height I'm going to set maybe to 1% or something very mild. Now, I'm going to also add a little bit of diffusion, or darkening, based on my alpha channel. So in the diffusion channel, I'm going to turn that on and then I'm going to load in my scum alpha texture and choose Ok. What this does is it darkens my mildew in certain regions and if I adjust my mix strength here, I can, sort of, layer that right on top of my pre-existing material. Now the next thing I'm going to want to do is add in an alpha channel so that I can superimpose this on my grout.
So I'm going to go to my Alpha channel, turn that on, and I'm going to click on those three dots next to texture. And I'm going to load in that same scum alpha map. That gives me something like this and I'm now going to apply this material to my wall/grout object. And now when I render I get this, it's pretty good but it looks like it just sort of a general wash of this mildew. It doesn't look like it's growing in clumps. So to achieve that look, I'm going to click on the triangle next to texture and use my filter shader. I'm going to click on my filter shader and turn on clipping. Clipping is what allows me to add clumps of things. So I'm going to take my high clip value and drag it over to the left and that's going to really darken up my mildew on my surface.
There are now regions that are totally mildew and now I'm also going to adjust the low clip and bring that fairly close to the high clip in order to ensure that there are quite a few regions that have no mildew whatsoever. And this gives me that nice clumping appearance. Now a problem that I have right now is that the mildew now appears a little bit too dark. Its a little overwhelming so I'm going to lower the brightness of this material slightly. So that some of the grout is still showing through. If I didn't want to do that, I could also go to my diffusion channel, and lower the strength of my diffusion to ensure that my material is not being overwhelmed by this diffusion channel. So for me, I guess, a mix strength of about 25% is working pretty well. I'm going to close my material editor here, and render out a preview. Certainly there's some room for some tweaking here, but I'd say it's a pretty good looking result.
As you create your materials, think about what happens to them on a day-to-day basis. With some creative layering, you can create realistic wear and tear on a surface, or in this case, active neglect.
- Applying materials to objects, NURBs caps, and polygon selections
- Creating glass using transparency and refraction
- Building colorful backgrounds
- Creating plastic, metal, and concrete
- Mapping an image to a video screen
- Adjusting material placement
- Creating layered materials with photographs and the Filter shader