Organic Materials

Organic Matter Simulation, What is it?

In this new blog post, I want to go over organic matter simulation. This means the simulation of natural materials within 3D programs. This is especially Hard task for real-time rendering as there is a lot of different factors that come into play while making this kind of material. Within this post, I'd like to go over a few of the main techniques used in industry standard level to simulate natural shading.

To make this a little bit easier, I'd like to split this into two sections the surface materials and the subsurface materials. With this I mean to say, that there are two different levels to natural materials. The first level is on the top, the thing that you able to see straight away this includes the colour the texture and any and all things located on the top level of a natural or organic objects surface. The second layer the subsurface layer is anything there is underneath this is a little bit more complicated as it includes how light disperses within the skin and also within other naturally occurring materials but also includes some of the Colour the texture and the opacity of what happens underneath the top layer. Within grass, within skin within any type of living material, there are often many layers that make up the full range of colour depth and the rest of the visuals.

For this blog post, I wanted to go through the content example given by epic games. This content example is one of many that comes with Unreal Engine and can be download from the marketplace. The reason I wanted to go through this example is that it accurately lays out the best methodologies towards achieving organic matter simulation in real time.

In this image, we can see the finalised render. This shows a man's head and the bust of him and accurately shaded skin featured all over his material. His eyes are closed her so we cannot see eyes. This is important to note, as eyes can often have very interesting materials assigned to it. So, let's break it down. The base we can see a fairly constant material of the singular colour featured all over his bust. With this, we can see a circular amount of specular diffusion. This means that there is not just an iridescent glow, but also the shininess of the material is dispersed evenly so that it doesn't give off a mirror shine. This is a good example of layered materials. We can see all of this colour and diffusion on the surface layer but we also see the dispersion of light as it goes through this later on onto the 2nd. This is a good example of subsurface scattering. Now, we can see that there is a lot to break down here but it's actually fairly simple.

As stated before, the two layers work in tandem. The subsurface layer is really important for the overall effect of the material. Within real-time rendering is really important to remember the light is very expensive. What this means is that it can cost a lot to the system when individual light rays are calculated. Hopefully in the future, we will see a further push for real-time Ray tracing lighting but unfortunately, this cannot be done yet on our current hardware. At the time being, we need to rely on more primitive forms of light. This means that instead of being able to accurately achieve physical based rendering we instead have to try and emulate it with cheats and shortcuts.

I have taken the time this week to look through and thoroughly study this content example given to us by epic games through the Unreal Engine. This is allowed me to learn a lot about industry-standard skill sets that are required to create realistic renders in real time. This blog post is a little bit different as the work done here was more of an evaluative nature than it was of actual creation on my part. This has lead me to create my own set of materials though they are almost exact copies of the content examples but done in a different project on a newer version of Unreal Engine. These materials were applied to different meshes but the overall appearance of them is greatly hindered by the primitive form of its shape, for example, a sphere. It would be lovely to carry on this research and development into organic matter simulation by applying these textures onto a more natural form of a mesh. I do not think that I will have enough time for the snow is likely that this will not happen during this development cycle but I will take these lessons and apply them to future projects most notably my final major project for this year.