Join Brian Bradley for an in-depth discussion in this video Understanding brute force GI, part of V-Ray 3.0 for 3ds Max Essential Training.
- Brute Force is a term applied to a problem solving method that simply tries all possible permutations available in order to crack a given problem. Because the Brute Force GI mode in V-Ray adopts this try all possible permutations approach it is a system that is theoretically capable of producing a perfect GI solution. The Brute Force GI engine, which was for a brief time called DMC GI in V-Ray, is a calculation method that in many ways is the opposite of the Light Cache system that we have already looked at.
It is extremely good at picking out detail in a scene, it can be slow, sometimes very slow when asked to calculate a high number of light bounces in an environment, it is not adaptive in any way at all, it has very few interface controls, two in fact, and is generally at its most effective when used as the Primary bounce engine. Unlike the biased irradiance mapping and Light Cache systems, Brute Force recomputes GI values for every single shaded point, doing so separately and independently for each and every sample point in the scene.
No interpolation, no averaging across points, indeed no sharing of information between samples in any way at all. One big plus to this approach comes in the form of memory usage. The Brute Force method uses hardly any RAM at all whilst making its calculations, which of course is quite different to the irradiance map and Light Cache systems. Both of which need to store the current version of their respective map types in random access memory. The basic calculation process of the Brute Force GI method is as follows.
As Brute Force is also a view-dependent GI technique the initial rays are traced from the rendering camera in the scene and are used to determine locations for sample points that the engine will use in its calculation of the final GI solution. Once that process is complete, if Brute Force is set as the Primary bounce engine, multiple rays are traced from each of the sample points that have been placed. The exact number of which will be dependent on the value we set in the Brute Force Subdivs perimeter.
If instead Brute Force is set to be used as the Secondary bounce engine then from every point on a surface that has been hit by a primary ray, let's say for example that irradiance mapping has been set as the Primary bounce engine, then a single secondary bounce ray will be traced from each irradiance point. The number of subsequent bounces those secondary rays can take will be determined by the value we set in the Brute Force Bounces perimeter. With a basic understanding of the Brute Force system under our belts then let's move on one last time in this chapter and take a look at actually putting Brute Force GI to work in our interior test scene.
- Using the new UI elements, Quick Settings, and revamped Frame Buffer
- Understanding color mapping modes
- Adding V-Ray light types
- Working with the V-Ray Sun and Sky systems and dome light
- Using irradiance mapping and light cache
- Working with diffuse color maps
- Making reflective materials
- Creating a translucency effect
- Using the new SSS and skin shaders
- Ensuring quality with image sampling
- Working with the adaptive subdivision engine
- Controlling the physical camera
- Working with FX tools such as VRayFur and VRayMetaball
- Stereoscopic 3D rendering
- Using Render Mask
Skill Level Intermediate
Q: This course was updated on 02/02/2016. What changed?
A: We added tutorials on the new 3ds Max camera tool, which replaces the defunct V-Ray Physical Camera. The author also includes a method for creating a V-Ray camera via scripting.
Q: This course was updated on 04/19/2018. What changed?
A: New videos were added that cover V-Ray 3.1 to 3.3 updates.
SketchUp: Rendering with V-Ray 3with Brian Bradley4h 15m Intermediate
V-Ray: Control Color Bleed in SketchUpwith Brian Bradley1h 2m Intermediate
Introduction and Important Information
V-Ray 3.1 to 3.3 Updates
V-Ray 3.4 to 3.6 Updates
1. Getting Ready to Render with V-Ray
2. Key Lighting Tools
3. Global Illumination
4. V-Ray Materials and Maps
5. Quality Control with Image Sampling
6. Working with Cameras: The V-Ray Physical Camera
7. Working with Cameras: V-Ray 3 & the 3ds Max Physical Camera
8. The V-Ray FX Tools
What's next?1m 47s
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