This is definitly the best Monday Movie yet. My tone is consistent, the video is clean and neat, and I barely had to do any audio editing at all. Eventually I might even get serious with these and start adding in watermarks and little intro “swoosh” logos or something!

But anyway. This Monday Movie is about how you should go about starting to learn Sub-Surface scattering in 3d studio max. It can seem daunting at first, but I show you how to properly set up a scene for testing, and where you should start when using the material. It’s a great primer!

Transcription

Monday Movie #2: Sub-Surface Scattering
Hello, everyone. Welcome to another Monday Movie. I'm Mr. Bluesummers.
Today I'd like to go into some detail regarding the sub-surface scattering "fast skin material" in 3d Studio Max. It's been in mental ray for a few versions now, but it was never integrated all that well so I'd like to make a "one-stop-shop" where you can go to get an idea of how you should be testing with this material. The environment that's most conducive to testing. I'd also like to show you a few features that will get you up and running quickly. I won't go into too much detail- that's for you to experiment with on your own. I just want to get you working as quickly as possible. Let's have a look around the scene. I've created a typical studio setup- I have my backdrop and I have a point light. I'm using only one light. I'm not using a 3-point light setup or anything complicated because this is more about the material than it is about the lighting. This one source, I'll also indicate, is just a point light- it's not an area light at all. I do that because if we had soft shadowing it would muddy the effect and make it hard to see the sub-surface scattering in action. Of course, I have to enable raytraced shadows- we want those nice harsh shadows. Another thing I did that I want to show you is (of course we're using mental ray- that's how we get the SSS material) but I've disabled final gather which is on by default. Again, same as the area shadows, the reason I turned that off is because if it's on it's just going to make it harder to see the sub-surface scattering. One more thing, I'm using logarithmic exposure control. I've found that when you're using photometric lights 3dsMax wants to push you toward photographic exposure control (which is really good in some instances) but I've found better results when you're testing with logarithmic exposure control. It's just easier and gives you better contrast. [EDITORS NOTE: I totally reverse position on this about a year and a half later]. Let me take a quick render and show you what we've got to start with. So you can see the harsh shadowing- this is the perfect setup for testing out a sub-surface material. Open my material browser here and I'm going to select all of my objects. Then I'll pick the sub-surface scattering material- "Fast Skin Material" and I'll apply it to all of these 3d objects. Let's take another render and see where changing the material drops us off. So I'm not sure if you'll be able to see it, but there's a little change in the borders where the transition from light to dark is extreme. These soft round objects, like the sphere and the knot, but where the shadows cast you can see it clearly. Let's take a look at some of these parameters of the material and see where we can start. We have a little bit of information about the lightmap- this lets you increase/decrease the render quality of the material. We can also add bumps if we wanted to using the typical mental ray bump shader (just like you would with a regular material). You can assign it a height, too. The fast skin material actually gives us 3 layers of sub-surface scattering because that most closely resembles the way that skin actually diffuses light. On the top level- the epidermal scatter- you have one type of scattering. One value and this would be how the top layer of skin will diffuse light. Behind that is the sub-dermal layer of scattering and this can be assigned a different color and a different weight. If the first layer isn't particularly diffusive, you can set the second layer to have a very high diffuse radius. The most common part of this material you see is the backsurface scattering. You know when you shine a flashlight through your fingers in a dark room? And you see that red color? That's what this is. It's that effect. Next, these are pretty self-explanatory; the reflection parameters let you set how shiney the skin material is. If the person has been running, you want him to look sweaty, you can alter the amount of reflectivity of the material and all skin has just a little bit of reflection at glancing angles in a Fresnel kind of way. You get some pretty robust options here. Finally, the advanced options, this is where you'll find the most important spinner in this material. It's down here; the "scale conversion factor". This spinner will let you tell mental ray how big your object is and mental ray will be able to scale the material accordingly. So these objects are relatively small in the worldspace. When I leave the scale conversion factor at "1" the material is too big. It's not scaling properly for the size of the object. I can change this to ".1" and when I re-render you'll really see a difference. Now honestly I have spent hours and hours of frustrating time trying to get this kind of change in my render simply by manipulating these diffuse weights, radius, and depth values. I would have had to turn them up to very extreme levels in order to get this kind of render. Instead all I had to do was alter this scale conversion factor so that's one of the first things you'll want to do when you're testing out this material. So there you have it. I think I've given you a good starting point for playing with this material on your own. I encourage you to do so because this is a lot of fun!
Mr. Bluesummers: www.MrBluesummers.com.
Thanks for tuning in to another Monday Movie. You can find all of my Monday Movies as well as tutorials, resources, and downloads, on my web site: www.MrBluesummers.com.