This first lesson will guide us through the process of setting up a simple scene. It provides a base understanding of the V-Ray Interface and where to find the most commonly used parameters.
You can download the lesson guide here.
Lesson 1 has three main parts: UI Overview, Rendering Modes and VFB (V-Ray Frame Buffer) which are annotated in the video. You can find scene files with the same names in the Lesson 1 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.
The first part of the tutorial covers the V-Ray interface in SketchUp. The main options can be found in the V-Ray Asset Editor - in here you can adjust the render settings, control the lights in the scene, create and adjust materials and work with V-Ray specific geometries.
In this example, we are going to use a simple Plane Light to illuminate our scene. We will only adjust the Intensity of the light here - all the lights are examined in more detail in the Extra videosof this lesson
We will also learn how to use the materials found in the V-Ray Material Library and how to properly set their scale/tiling
In the second part, we discuss the different ways V-Ray can render:
- Interactive - in this mode V-Ray starts rendering the whole image at once at a lower quality and then gradually increases the quality by clearing the noise. Every time we make a change to the scene (lights, materials, etc.) V-Ray refreshes the image. This mode is useful during shading and lighting as we can immediately see the effect of the change we made. This mode can use GPU acceleration. Interactive mode will continuously improve the quality of the image until we stop it and so it doesn’t have a quality control slider.
- Progressive - renders similarly to the Interactive mode - starts at lower quality and improves it with time. The main differences are that it will not restart if a change to the scene is made. You can put a time or noise limit for the rendering so it stops after a certain time has passed or certain quality is reached. Progressive rendering can use Global Illumination modes like Irradiance Map and Light Cache which require a prepass but speed up the calculation of GI. However, if you want to use GPU acceleration you need to use Brute Force as both Primary and Secondary GI engine. We can use the Quality slider to control the quality of the final image - it affects both the settings for antialiasing and the settings for Global Illumination.
- Bucket rendering - this is the original mode in which V-Ray used to render. It divides the image into regions and each region is assigned to a CPU core to render. It can use Global Illumination modes that require a prepass like the Progressive rendering but it cannot use GPU acceleration. We can use the Quality slider to control the quality of the final image - it affects both the settings for antialiasing and the settings for Global Illumination. This mode is the most memory efficient especially when we have things like V-Ray Proxies, V-Ray Fur or Displacement in the scene - these topics are discussed in the following lessons
VFB - V-Ray Frame Buffer
This module covers the basic settings of the V-Ray Frame Buffer.
- VFB history allows us to save multiple versions of our rendered image and compare them.
- The VFB can apply different color corrections to the image to improve the look of the image. Since the VFB holds the image in a 32 bit floating point format you have much more color information to work with and you can save the image with the color corrections applied.
This lesson comes with 8 Extra modules. For each module there is a video, and a scene file with the same name in the Lesson 1 folder.
You can download the lesson guide here.
1. Lights Plane
This extra module covers the Plane Light in more detail. The Plane Light is a physically accurate light source that has a physical measurable area which emits the light and the light decays (loses intensity) accurately as it travels through space. The shape and size of the light affect the softness/sharpness of the shadows cast by it.
Main settings - these settings are the same for all V-Ray lights:
- Color/Texture - allows you to pick a color for the light or use a texture file to control it
- Intensity - controls the strength of the light. This parameter depends on the Units parameter and in its default state (Units = Default(Scalar)) the value of the Intensity parameter directly affects the intensity values of the pixels of the light source when they are visible to the camera
- Units - the other possible settings here will be covered in the second Extra videos
Plane light specific options
- Shape - allows us to control the shape of the plane light - the available options are Rectangle and Ellipse
- Directionality - allows us to focus the light in the direction of the plane's normal.
2. Light Sphere
This extra module uses the Sphere Light to discuss the Units parameter and demonstrate how it relates to the light intensity and size. The Sphere Light is a physically accurate light source that has the shape of a sphere. It emits light in all directions equally and the light decays (loses intensity) accurately as it travels through space.
- Units - this parameter determines the unit used to determine the Intensity of the light. Using different units may be necessary when we are trying to match the intensity of a virtual light source to that of a real-world light.
- Default(Scalar) - this is the only mode that is not based on real world measurement units of light intensity. Instead when the Units is set to Default(Scalar) the intensity parameter directly controls the brightness of the light when it’s shape is directly visible by the camera, assuming no color/exposure corrections are applied. This means that the total amount of light emitted by the light source depends on its size - smaller lights emit less light and larger lights emit more light but the intensity of the light is a constant.
- Luminous power - sets the total "amount" of light emitted in Lumens, the amount of emitted light remains constant when changing the light size. This means that if you make a light smaller it will shine brighter, in order to emit the same amount of light from a smaller area and vice versa.
- Radiant power - sets the total "amount" of light emitted in Watts, the amount of emitted light remains constant when changing the light size. This means that if you make a light smaller it will shine brighter, in order to emit the same amount of light from a smaller area and vice versa.
- Luminance - sets the amount of light emitted in Lumens per unit of area - larger lights emit more total light than smaller lights with the same Intensity
- Radiance - sets the amount of light emitted in Watts per unit of area - larger lights emit more total light than smaller lights with the same Intensity
3. Spot Light
This extra module discusses the Spot Light - a light source that can create the effect of a flash light or spot light which focus the light in one area. This source emits the light from an infinitely small point in space so it cannot be seen by the camera or in clear reflections. The settings we discuss in the video are:
- Cone angle - the angle at which the spot light emits light
- Penumbra angle - the angle at which the light begins to fadeout to "no light"
- Penumbra falloff - determines how the light transitions from full strength inside the cone to no light outside the cone
- Decay - this parameter controls the method used to calculate how the light intensity diminishes as it travels away from the source. The physically accurate method is Inverse Square
- Shadow radius - this light source emits the light from an infinitely small point and thus it can only create sharp shadows. This parameter allows us to specify a radius of the shape of the light that is used only when calculating shadows. Larger numbers make the shadows softer.
4. Light IES
This extra module discusses the IES Light - A light source that allows us to introduce real world lights into the scene. Lighting manufacturers sometimes provide .ies files which hold photometric data for the lights they manufacture. You can use a V-Ray IES Light to load those files and have the physically accurate illumination in SketchUp.
- Intensity - usually the IES file holds information about the actual intensity of the light. However, this value can be overridden
- IES Light File - a slot for the .ies light profile
- Shape - specifies how the light shape is determined for the purposes of calculating soft shadows.
- From IES file - uses the shape information (when available) saved in the .ies file
- Point - the light is considered as a point - only can create sharp shadows
- Circle - the light shape is a circular plane, the normal of the plane is the direction of the light and the diameter of the circle is determined by the Diameter parameter
- Sphere - the light shape is a sphere, the size of which depends on the Diameter parameter
- Diameter - controls the softness of the shadows generated by the IES Light when the Shape parameter is set to either Circle or Sphere. Larger values make for softer shadows
5. Light Omni
This extra module uses the Point Light to examine some of the extra parameters of lights. A Point Light is an infinitely small point (like the Spot Light) that emits light in all directions equally. This light cannot be seen by the camera or in clear reflections. It creates sharp shadows by default. The Shadow radius parameter allows us to specify a radius of the shape of the light that is used only when calculating shadows. Larger numbers make the shadows softer.
- Affect Diffuse/Specular - allows you to enable or disable the effect of the light on the diffuse and specular components of the materials in the scene. This can be used for artistic purposes but disabling these checkboxes or using multipliers different than 1 will create physically inaccurate results
- Shadows - enables/disables the casting of shadows by the light
This module covers the workflow for rendering an animation with V-Ray.
7. Batch Rendering
This module covers the workflow for rendering multiple views of a scene using the Batch Render functionality of V-Ray.
8. Advanced VFB
This extra module goes deeper into some of the settings of the V-Ray Frame Buffer including:
- A/B comparison – allows you to compare images that were saved in the VFB History
- More detailed color corrections
- Saving/loading color corrections to a file – this can be useful when working on a project that has multiple shots and you want to all the images to have the same “feel”