Software:
Blender 2.79
Method A:
1) Select multiple objects
2) Alt + Click wanted parameter and change it
Method B:
1) Select multiple objects
2) Set the wanted parameter
3) right click parameter and choose ‘Copy To Selected’
* Do the same for grouped parameters like vectors using ‘Copy All To Selected’
Software:
3ds max 2017
Press Alt while using camera navigation tools, this will slow the movement significantly so you can place the camera very precisely.
Software:
3ds max 2017 | Maya 2018 | V-Ray 3.6
3ds max
Render a test with White Balance set to Custom with pure white color.
Let the rendering go on at least until the pixel values stabilize (the Denoiser works at least once..).
set the white balance custom color to a color sampled from the VFB at a point that you know should be appearing completely neutral (neither warm or cold)
Render again.
* Each time you want to test different sample locations you need to sample the pixels from the test rendered with custom pure white.
Maya
The procedure in Maya is identicle,
Add V-Ray Physical Camera attributes to the camera and enable them,
Create a test render with pure white White-Balance Color,
Sample the white/grey surface color in the V-Ray VFB (Render Window) to the White-Balance color, and render again.
To access V-Ray Physical Camera functionality in Maya,
V-Ray Physical Camera attributes must be added to the camera and enabled.
1) select the camera
2) In the attribute editor open the Attribute menu and choose V-Ray > Physical Camera
3) make sure treat as physical camera is enabled
* you can add more V-Ray Attributes to the camera like this
Software:
Blender 2.79
The Cycles ‘Input > Light Path’ node is useful for creating shaders with a selective optical participation.
A simple example of that would be a bright light material that is ‘seen’ by the camera and through reflection / refraction but isn’t actually lighting the scene.
Basic Ray Visibility can be set at the object level via the object’s Cycles setting:
But when we need to set per shader, and more specific Ray Visibility, we can set it up using a ‘Light Path’ node within the cycles shader:
The ”Is ________ Ray” outputs will give a 0 / 1 value indicating if the sampled ray is of a certain type,
The Ray Length output will give a float value representing the ray’s real world length,
And the ‘_______ Depth’ outputs will give an integer representing the number of light bounces that were computed until the sampled ray.
In this simple example we see how to use the Light path node to create a light shader that only affects reflections / refraction but not producing any diffuse light.
A Mix Shader is used to mix between a Transparent Shader and an Emission Shader.
The ‘Converter > Math’ ‘Maximum’ node is used as a logical ‘OR’ operator to produce a value of 1 for the mix factor if the ray type is either a Camera Ray or a Glossy Ray or a Singular Ray, and cause the Emission shader to be active.
For other ray types the mix value will be 0 and the Transparent shader will be active.
Basic Emission Shader:
Restricted Emission Shader:
* At the time of writing this post the ‘Is Diffuse Ray’ output of the ‘Light Path’ node didn’t produce expected results so I couldn’t create a light material that creates diffuse lighting but doesn’t appear in reflections and refractions.
From the Cycles documentation:
Ray types can be divided into four categories:
Reflection and transmission rays can further have these properties: