Rendering is all about Light; light intensity, light falloff, light refraction, and light reflection. To create a realistic 3D object (or space), you basically control a bunch of 3D masses, textures, and how light reacts to all of them. It may sound a complicated process, but modern technology is making this easier every day. VRay Next is a prime example!
This is where Normal Maps come to play, they’re a way to control how light reacts to a certain mass or object and create a more realistic 3D render.
What is a Normal Map
To understand Normal Maps, we first need to understand how Bump Maps work.
Bump Maps are a way to create the illusion of details to a texture. They create fake dimensions, patterns, and/or reflections to an otherwise flat image applied to a smooth 3D object.
The thing about Bump Maps, though, is that they’re Greyscale. To a Render Engine they translate to Up and Down (White is Up, Black is Down, Greys are In-between Heights). So they’re basically 2D.
Normal Maps on the other hand are 3D; they’re a colorful map of different shades of Reds, Greens, and Blues (RGB). The RGB values correspond to the XYZ Axes of a 3D space; so a Render Engine doesn’t just read ‘Up and Down’ dimensions from that map, hence they create a more detailed surface.
How to Create a Normal Map
When I first heard about how awesome Normal Maps are and how Realistic they make Render Scenes, I wanted to create my own. I have a habit of creating my own Texture Maps.
After a lot of Google search and too many frustrated attempts on Photoshop I was ready to give up (Apparently CS6 Extended doesn’t have all the 3D tools anymore, and I’m not changing my version anytime soon!).
One very lucky day I stumbled on this website. IT’S A FREE ONLINE NORMAL MAP GENERATOR. And it’s AMAZING. Excuse the excited caps..
The process was fairly easy. I just uploaded my Texture Map of choice and used all the default settings.
You can also create a Displacement Map, a Specular Map (Reflection), and an Ambient Occlusion Map (which I never met anyone who uses it in VRay for Sketchup). Go ahead and give this site a try, it’s worth it!
Rendering with a Normal Map vs Bump Map
I gave rendering with a Normal Map a try a few times before (whenever they were available) but I never really paid attention to the difference between using a Normal Map vs Bump Map.
So I made a small test for the benefit of this post and for my own benefit. First, I rendered an object with a rough wood texture using the Specular, Bump, Displacement Map that came with it.
The results are pretty decent; the details and reflections look good.
I went to the website above and tinkered a bit to produce my own Normal, Displacement & Specular Maps. I added them to my Texture the usual way.
while testing out my render, at first I thought there isn’t any difference between using a Bump vs using a Normal Map. But with a closer look, the material has a better shadow distribution and the details just look more “real” or “3D”. You can easily believe that the object has been modeled with these details and that it isn’t a texture map because of how the light falls on the surface.
I started using a Normal Map whenever I created a new custom material, or whenever I had the chance to update an old one; I download the Texture Map I want and just drag & drop it in the Online Generator, then click ‘All’ to download everything. Sometimes I do little tweaks to the maps vie the sliders, but it’s rare.
It may seem like a bit of work, but it’s worth it.
Hope this article has helped you with figuring our Normal Maps & in creating your own.
Have you ever used a Normal Map? Do you prefer Bump Maps or Normal Maps? Let me know in the comments below! 🙂