In this article by Ciro Cardoso, author of the book Lumion3D Best Practices, we will see materials, and why they are essential. In the 3D world, materials and textures are nearly as important as the 3D geometry that composes the scene. A material defines the optical properties of an object when hit by a ray of light. In other words, a material defines how the light interacts with the surface, and textures can help not only to control the color (diffuse), but also the reflections and glossiness.
(For more resources related to this topic, see here.)
It’s not difficult to understand that textures are another essential part of a good material, and if your goal is to achieve believable results, you need textures or images of real elements like stone, wood, brick, and other natural elements. Textures can bring detail to your surface that otherwise would require geometry to look good.
In that case, how can Lumion help you and, most importantly, what are the best practices to work with materials? Let’s have a look at the following section which will provide the answer.
A quick overview of Lumion’s materials
Lumion always had a good library of materials to assign to your 3D model, The reality is that Physically-Based Rendering (PBR) is more of a concept than a set of rules, and each render engine will implement slightly differently. The good news for us as users is that these materials follow realistic shading and lighting systems to accurately represent real-world materials.
You can find excellent information regarding PBR on the following sites:
http://www.marmoset.co/toolbag/learn/pbr-theory
http://www.marmoset.co/toolbag/learn/pbr-practice
https://www.allegorithmic.com/pbr-guide
More than 600 materials are already prepared to be assigned directly to your 3D model and, by default, they should provide a realistic and appropriate material. The Lumion team has also made an effort to create a better and simpler interface, as you can see in the following screenshot:
The interface was simplified, showing only the most common and essential settings. If you need more control over the material, click on the More… button to have access to extra functionalities. One word of caution: the material preview, which in this case is the sphere, will not reflect the changes you perform using the settings available. For example, if you change the main texture, the sphere will continue to show the previous material.
A good practice to tweak materials is to assign the material to the surface, use the viewport to check how the settings are affecting the material, and then do a quick render. The viewport will try to show the final result, but there’s nothing like a quick render to see how the material really looks when Lumion does all the lighting and shading calculations.
Working with materials in Lumion – three options
There are three options to work with materials in Lumion:
- Using Lumion’s materials
- Using the imported materials that you can create on your favorite modeling application
- Creating materials using Lumion’s Standard material
Let’s have a look at each one of these options and see how they can help you and when they best suit your project.
Using Lumion’s materials
The first option is obvious; you are using Lumion and it makes sense using Lumion’s materials, but you may feel constrained by what is available at Lumion’s material library. However, instead of thinking, “I only have 600 materials and I cannot find what I need!”, you need to look at the materials library also as a template to create other materials.
For example, if none of the brick materials is similar to what you need, nothing stops you from using a brick material, changing the Gloss and Reflection values, and loading a new texture, creating an entirely new material. This is made possible by using the Choose Color Map button, as shown in the following screenshot:
When you click on the Choose Color Map button, a new window appears where you can navigate to the folder where the texture is saved. What about the second square? The one with a purple color? Let’s see the answer in the following section.
Normal maps and their functionality
The purple square you just saw is where you can load the normal map. And what is a normal map? Firstly, a normal map is not a bump map. A bump map uses a color range from black to white and in some ways is more limited than a normal map. The following screenshots show the clear difference between these two maps:
The map on the left is a bump map and you can see that the level of detail is not the same that we can get with a normal map. A normal map consists of red, green, and blue colors that represent the x, y, and z coordinates. This allows a 2D image to represent depth and Lumion uses this depth information to fake lighting details based on the color associated with the 3D coordinate.
The perks of using a normal map
Why should you use normal maps? Keep in mind that Lumion is a real-time rendering engine and, as you saw previously, there is the need to keep a balance between detail and geometry. If you add too much detail, the 3D model will look gorgeous but Lumion’s performance will suffer drastically. On the other hand, you can have a low-poly 3D model and fake detail with a normal map.
Using a normal map for each material has a massive impact on the final quality you can get with Lumion. Since these maps are so important, how can you create one?
Tips to create normal maps
As you will understand, we cannot cover all the different techniques to create normal maps. However, you may find something to suit your workflow in the following list:
- Photoshop using an action script called nDo: Teddy Bergsman is the author of this fantastic script. It is a free script that creates a very accurate normal map of any texture you load in Photoshop in seconds.
To download and see how to install this script, visit the following link:
http://www.philipk.net/ndo.html
Here you can find a more detailed tutorial on how to use this nDo script:
http://www.philipk.net/tutorials/ndo/ndo.html
This script has three options to create normal maps. The default option is Smooth, which gives you a blurry normal map. Then you have the Chisel Hard option to generate a very sharp and subtle normal map but you don’t have much control over the final result. The Chisel Soft option is similar to the Chisel Hard except that you have full control over the intensity and bevel radius. This script also allows you to sculpt and combine several normal maps.
- Using the Quixel NDO application: From the same creator, we have a more capable and optimized application called Quixel NDO. With this application, you can sculpt normal maps in real-time, build your own normal maps without using textures, and preview everything with the 3DO material preview. This is quite useful because you don’t have to save the normal map and see how it looks in Lumion. 3DO (which comes free with NDO) has a physically based renderer and lets you load a 3D model to see how the texture looks.
Find more information including a free trial here:
http://quixel.se/dev/ndo
- GIMP with the normalmap plugin: If you want to use free software, a good alternative is GIMP. There is a great plugin called normalmap, which does good work not only by creating a normal map but also by providing a preview window to see the tweaks you are making.
To download this plugin, visit the following link:
https://code.google.com/p/gimp-normalmap/
- Do it online with NormalMap-Online: In case you don’t want to install another application, the best option is doing it online. In that case, you may want to have a look at NormalMap-Online, as shown in the following screenshot:
- The process is extremely simple as you can see from the preceding screenshot. You load the image and automatically get a normal map, and on the right-hand side there is a preview to show how the normal map and the texture work together. Christian Petry is the man behind this tool that will help to create sharp and accurate normal maps. He is a great guy and if you like this online application, please consider supporting an application that will save you time and money.
Find this online tool here:
http://cpetry.github.io/NormalMap-Online/
- Don’t forget to use a good combination of Strength and Blur/Sharp to create a well-balanced map. You need the correct amount of detail; otherwise your normal map will be too noisy in terms of detail.
However, Lumion being a user-friendly application gives you a hand on this topic by providing a tool to create a normal map automatically from a texture you import.
Creating a normal map with Lumion’s relief feature
By now, creating a normal map from a texture is not something too technical or even complex, but it can be time consuming if you need to create a normal map for each texture. This is a wise move because it will remove the need for extra detail for the model to look good. With this in mind, Lumion’s team created a new feature that allows you to create a normal map for any texture you import.
After loading the new texture, the next step is to click on the Create Normal Map button, as highlighted in the following screenshot:
Lumion then creates a normal map based on the texture imported, and you have the ability to invert the map by clicking on the Flip Normal Map direction button, as highlighted in the preceding screenshot.
Once Lumion creates the normal map, you need a way to control how the normal map affects the material and the light. For that, you need to use the Relief slider, as shown in the following screenshot:
Using this slider is very intuitive; you only need to move the slider and see the adjustments on the viewport, since the material preview will not be updated. The previous screenshot is a good example of that, because even when we loaded a wood texture, the preview still shows a concrete material.
Again, this means you can easily use the settings from one material and use that as a base to create something completely new. But how good is the normal map that Lumion creates for you? Have a look for yourself in the following screenshot:
On the left hand side, we have a wood floor material with a normal map that Lumion created. The right-hand side image is the same material but the normal map was created using the free nDo script for Photoshop. There is a big difference between the image on the left and the image on the right, and that is related to the normal maps used in this case. You can see clearly that the normal map used for the image on the right achieves the goal of bringing more detail to the surface. The difference is that the normal map that Lumion creates in some situations is too blurry, and for that reason we end up losing detail.
Before we explore a few more things regarding creating custom materials in Lumion, let’s have a look at another useful feature in Lumion.
Summary
Physically based rendering materials aren’t that scary, don’t you agree? In reality, Lumion makes this feature almost unnoticeable by making it so simple. You learned what this feature involves and how you can take full advantage of materials that make your render more believable. You learned the importance of using normal maps and how to create them using a variety of tools for all flavors. You also saw how we can easily improve material reflections without compromising the speed and quality of the render.
You also learned another key aspect of Lumion: flexibility to create your own materials using the Standard material. The Standard material, although slightly different from the other materials available in Lumion, lets you play with the reflections, glossiness, and other settings that are essential. On top of all of this, you learned how to create textures.
Resources for Article:
Further resources on this subject:
- Unleashing the powers of Lumion [article]
- Mastering Lumion 3D [article]
- What is Lumion? [article]
