Main Modules



The forth lesson covers the wide range of materials and textures that come with V-Ray

You can download the lesson guide here.

Each section is annotated in the video. You can find scene files with the same names in the Lesson 4 folder. These were made so that you can start at any one of these stages and follow the steps in the video to the end.

 

 

<iframe src="https://player.vimeo.com/video/230416591" width="640" height="400" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>

 

 

Library Materials


V-Ray for Sketchup comes with an extensive materials library that can be used directly. Since some of the materials use textures it is necessary for the user to manually set up the tiling of the texture by either adjusting its size or changing the UV tiling as seen in the video. All materials in the V-Ray materials library can be edited which allows us to start with a material that is similar to what we need and then further adjust it to meet our needs.

 

New Materials


Generic

In this section, we will shade our scene starting from scratch and using the Generic V-Ray material. This is the standard V-Ray Material which allows us to create a wide range of physically accurate shaders. You can use textures to control most of its settings like diffuse, reflection, refraction, glossiness etc. and add bump and displacement mapping. We will create materials like Paint, Metal and Glass and in the process, we you will be able to see how the main parameters of the Generic material work. The commonly used parameters are:

Some of the parameters like DiffuseReflect and Refraction are controlled by a color swatch. It is a good idea to avoid setting those to completely black or completely white as this is not physically accurate. Setting the Diffuse or Reflect to completely black means that the object reflects no light at all (it is a black hole) and setting those parameters to completely white means that the object reflects all the light back to the environment which is again impossible. Additionally, if you set the Diffuse to completely white this may lead to slow render times when GI with Light Cache is used. You may use black for Reflect and Refract if you want to create a material that is completely diffuse. But those parameters should never be pure white even for very reflective or refractive materials.

 

Emissive Material

The Emissive material is used to shade objects which are supposed to emit light i.e. phone or tv screens, lights with a complex shape etc. The material settings are pretty straight forward but it is important to note that objects with this material do not shine direct light into the scene. This means that if we want the objects to illuminate the scene we require GI with very high settings

 

Two Sided Material

The Two Sided material is used to simulate thin translucent materials like paper, fabric, thin leaves etc. The effect of the material can be seen only when we have a direct light source behind the geometry and the geometry doesn’t have a volume i.e. it is a plane. The settings are very intuitive:

 

Subsurface Scattering Material

The Subsurface Scattering Material is used to simulate materials like skin wax fruit etc. It has Diffuse, Sub-surface scattering and Specular (reflections) layers. This material is greatly affected by the scale of the geometry. That is why it has a Scale parameter which allows us to adjust the way it looks without having to scale our scene.

The options in the Specular layer are the same as in the Reflection layer of the Generic material with the only difference being that you have a Specular Amount parameter which allows us to control the strength of the Specular layer.

 

Procedural Textures


This section covers the usage of procedural textures to control some of the parameters of the V-Ray Material. Procedural textures are textures that are generated using a mathematical description or algorithm.

Color Correction Map

The Color Correction Map allows us to color correct a texture (bit map or procedural) inside SketchUp. This can be useful when we need to fine tune the colors of a texture and we do not want to constantly switch between photoshop and SketchUp. Using V-Ray Interactive rendering and the color correct texture we can quickly get the result we need.

Noise Map and Bump

The Noise texture is commonly used in CG. It allows us to add some randomness to a parameter. In this case we use it as a bump map to add small detail to the wall. Bump mapping is a shading technique to fake small bumps and dents on the surface of our geometry.

 

Displacement


In this section, we use Displacement mapping instead of Bump mapping. The difference between the two is that bump mapping is a shading effect - it changes the surface normals of the shaded point so that it looks as if there are dents and bumps but the original geometry remains unchanged. This is clearly visible if you look at the geometry at a steep angle, you will see that the surface is actually flat. Displacement on the other hand subdivides the original mesh into much finer mesh and then displaces the new faces based on the texture. This creates brand new geometry. The effect is much more accurate and looks much better than bump mapping but it is also harder to calculate as it requires more RAM (to store the new geometry) and more raytracing for all the new faces in the scene.

 

Export Materials To A Library


In this section, we cover the process of exporting a material to a library. This allows us to store materials that we often use or to share materials with coworkers.

 

 

Extra Modules



This lesson comes with 2 Extra modules - Advanced Materials and Advanced Textures. For each module, you can find a scene file with the same name.

You can download the lesson guide here.

1. Advanced Materials


 

 

<iframe src="https://player.vimeo.com/video/230467502" width="640" height="400" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>

 

 

In this module, we go over some of the less commonly used materials:

Car Paint Material

Car Paint Material - created to simulate car paints the material can be used to simulate a wide range of metallic surfaces that have a clear coat on top of them. It has three layers - Base, which gives the base color and reflectivity of the material, Flakes which allows us to add tiny flakes on top of the base layer and Coat which adds a clear coat layer over the bottom two layers.

The Coat layer is similar to the Reflection layer of the Generic V-Ray Material but with Fresnel Reflections always enabled. This allows us to quickly add a thin reflective coat over our Baseand Flakes layers:

 

Blend Material

Blend material – A special material that allows us to combine multiple materials and blend them together using a grayscale value (color or texture).

 

Bump Material

Bump material – allows us to add a bump map to any material we have in the scene - some materials do not have a bump map slot in their settings and this material is the only way to add bump to them. Stacking multiple Bump Materials together can create a more complex surface material by allowing the use of several bump maps together easily

 

Hair Material

Hair material – a material designed for shading of hair specifically. It has a Diffuse component, two different reflective components and a Transmission (translucent) component. The DiffusePrimary and Secondary Specular layers contribute to the way the hair looks when illuminated from the front. The secondary reflection layer represents the part of the light that enters the hair strand and is reflected back to the camera, that is why it depends on the transmission color. The Transmission color contributes to the way the hair looks when it is illuminated from behind.

 

2. Advanced Textures


 

 

<iframe src="https://player.vimeo.com/video/230469291" width="640" height="400" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>

 

Dirt Map

Dirt Map – a V-Ray specific map that is procedurally generated during rendering. It returns one of two colors (occluded or unoccluded) or a blend between the two depending on whether or not there is geometry close to the shaded point. This allows us to simulate effects like dirt gathering in crevices or wear on edges of the geometry. However, the texture is mainly used to create an ambient occlusion pass. The AO pass darkens the image where the objects are close together in a way fake-simulating contact shadows.

 

Curvature Map

Curvature - the curvature texture is somewhat similar to the Dirt Map. It allows us to sample a geometry and detect its curvature. The texture will then return dark values for areas that are dents or holes and lighter values for the peaks. We can then use this texture to shade these areas differently by using it to control a Blend Material and blend different shaders. Setting up this texture requires a bit of experimentation because it greatly depends on the scene scale.

 

Edges Texture

Edges texture - returns one color for the faces of a mesh - Background Color and another color for its edges – Edges Color. The texture can be used in a Bump map slot of a material which will smooth out the sharp edges of the geometry. It is important to note that this is only a shading effect and the original geometry will not be smoothed.

 

TriPlanar Map

TriPlanar - this texture allows us to assign bitmap or other 2d textures to objects that do not have proper UVs. The texture projects (one or more) textures along the local axes of the object.