This is my second Houdini tutorial, in collaboration with cmiVFX. It’s about shading and rendering in Houdini using Mantra. In this video I talk about a lot of subjects, such as Materials, Rendering tools, Direct and Indirect lighting, Global Illumination, Displacement, details about Mantra and others.
Throughout this tutorial, as an application, I build, step by step, the Materials and render setup for the ‘Tea Set’ scene.
Introduction to Materials
A very important step prior to the rendering process is defining the aspects of the surface of your objects. This action is achieved in a wide variety of ways in Houdini and is crucial to start somewhere neutral. Learn how you can create materials and how you can assign them to your objects as well as components.
Materials In Depth
To have a deep understanding of what makes a material believable, its important to understand the materials pipeline. Houdini extends its procedural workflow into all aspects of the application including shading networks. Its important to know the many ways of application to surfaces. In addition to that, Houdini lets you compile the shaders inside of it in a unique way. It lets you not only write shaders with code but with visual blocks called vops as well. Knowing that, the artist will need to have options, and we will go through these options on how to create better, proper materials for your objects.
Houdini has a lot of rendering tools that can benefit its users when working. We explore different tools like the render region tool, render view, MPlay, render nodes or output drivers, comparison tools and more. This will allow the artists workflow to be optimized for speed. Waste less time performing long test renders and spend more time tuning your look.
Introducing The Project
We create real projects at cmiVFX and we are happy to delve deep into a project that utilizes almost all of the rendering technology in Houdini. In this section, the project is introduced. The final result of this project is discussed as well as its modeling and UV sets used in the scene.
Direct And Indirect Lighting
The rendering process as a whole, is about calculating the interaction of the lighting in the scene and outputting the result. Knowing about light and its physical properties is a very important step to understanding how to work out lighting inside any software. Understanding direct and indirect light is discussed in length with charts and graphs.
In order to get to the next level of lighting calculations comprehension, We will show the methods of normal propagation for surface shading using the information gathered earlier. This resulting data helps create a translucent material inside Houdini.
With the information gathered so far about the importance of the indirect illumination we`ll go trough different ways to create indirect illumination inside Houdini, like the VEX global illumination light shader, PBR, photon mapping . etc, and also talk about one of the methods on how you can have indirect illumination on a per object basis. Let’s investigate Image Based Lighting and how you can convert an image to the .rat format preferred by Mantra. Next, how to apply indirect illumination and light linking.
This section is geared to guide you on how to apply your created materials to the main project, finishing the lamps surface shaders, then working on the materials that do not need texturing for other objects in the scene.
Once you have created UV’s for geometry you can assign procedural or image based textures to surfaces. This task and others, like creating the corresponding materials for our objects and texturing them will be covered in a step by step method. Understanding COP networks to modify an image, then use the output as a texture for one of the materials is a focus in this portion of the video.
Displacement mapping is a very important way to add details to your objects without high resolution modeling. Having a good grip on how to create some displacement shaders for materials is essential. Navigate through shader view and use important parameters like the displacement bound and true displacements.
Finishing Touches, Sampling In Mantra And Rendering The Scene
Fine tuning and looking good.. That is what this chapter is all about. What makes a shader and light good and final?. Working on finishing touches, like adding some objects to reflect in our render, adding some lights, making some reflections and light linking and many other subjects compose the final touches of a our project. Mantra is a powerful rendering engine, one of the best in the industry, but as any other beasts it need to be mastered. Knowing how to manage samples from the inside out is a phenomenal for fine tuning your scenes. We are going to look deep into how Mantra manages samples, also as an additional bonus we will have an overview on how Depth of Field works in Mantra to achieve our final result.