Arnold MtoA DomemasterStereo

Andrew Hazelden edited this page Apr 28, 2017 · 8 revisions

Overview

Arnold Domemaster3D Shelf

The DomemasterStereo shader is added to a Maya scene using the ArnoldDomemaster3D Shelf tool.

When you run the DomemasterStereo shelf tool it adds a custom ArnoldDomemasterStereo camera rig to the scene that has the left and right cameras set up automatically. The left camera DomemasterStereo attributes are used to drive the stereoscopic settings for both the left and right cameras. This means you only have to change the Zero Parallax Sphere or Camera Separation setting in one place.

To change the DomemasterStereo attributes, select the camera in your scene. Open the attribute editor and switch to the camera's shape node. The lens shader is listed in the Arnold section.

Known Issues

Arnold 5 Compatibility Note: The new Arnold 5 release has changed their lens shader system. At this point in time the current Domemaster3D shaders are not compatible with Arnold 5. If you need a lens shader today that works with Arnold 5 it is recommended you use the new built-in "VR Camera" module provided by Solid Angle directly.

The current version of the Arnold Domemaster3D shaders for Maya are a development build. At this point in time there is no easy way to create screen space texture maps using Arnold's MtoA, HtoA, C4DtoA, and SItoA render nodes. This means a solution has to be developed inside the Domemaster3D shaders that will remap an existing texture map into screen space coordinates.

At this point, the DomemasterStereo shader will render a stereo fulldome image but you will notice something that looks like a small "swirly region" in the zenith part of the fulldome frame. This is due to a lack of a screen space turn map texture.

Domemaster Stereo Shader Controls

DomemasterStereo Shader Attributes

Camera: Choices are Center/Left/Right. Selects the camera to use for rendering. Center skips 90% of the calculations and gives you a highly optimized standard latlong image.

Field of View: Controls the field of view for the rendered angular fisheye image. A "Domemaster" formatted image has a 180 degree field of view, and a "light probe" style angular image has a 360 degree field of view.

Zero Parallax Sphere (focus plane): This is the distance at which the left and right camera's line of sight converges.

Camera Separation: The initial separation of the left and right cameras.

Dome Forward Tilt: Dome tilt in degrees. Note that this value is not used unless you enable Dome Tilt Compensation.

Dome Tilt Compensation: Enabling this option, shifts all the calculations by the # of degrees specified in Dome Forward Tilt. Basically, it keeps the fulldome cameras / viewer's head vertical while the dome rotates forward.

Vertical Mode: Enables the vertical dome mode which automatically adjusts the head turn setting and adds a turn compensation for the upper and lower part of the dome. It's a simplified and optimized version of the Dome Tilt Compensation with a 90 degree tilt angle, but with a different automatic handling of the top and bottom pinch correction. It is faster and easier to use.

Custom Maps

Separation Map: A value between 0-1 that multiples the Camera Separation. This attribute is meant to be used with a grayscale texture mapped to the screen space. It's used to control the amount of 3D effect, and eliminate it where desired.

Head Turn Map: A value 0-1 that controls the amount of the head turn. This attribute is meant to be used with a grayscale texture mapped using the screen space. Typical use, keep the head straight while looking at the top of the dome.

Head Tilt Map: A value 0-1 (with 0.5 being the "neutral" value) that tilts the cameras (or head) left/right. This attribute is meant to be used with a grayscale texture mapped using the screen space. 0 means 90 degrees to the left, 1 means 90 degrees to the right.

Image Orientation

Flip X: Flips the view horizontally

Flip Y: Flips the view vertically

Options

Exposure: This attribute allows you to control the overall brightness of the final rendered frame.

Screen Space Texture Maps

You can control the stereoscopic effect seen in the LatLongStereo and DomemasterStereo shaders with the help of control texture maps.

The DomemasterStereo shader's Separation Multiplier, Turn Multiplier, Head Tilt attributes support control texture mapping. The images have to be applied using screen space coordinates.

Comfortable Stereo Settings

Here is a little tip that will help you work out some initial "comfortable" stereo settings to use in the Domemaster3D lens shaders:

Use Maya's distance measurement tool to check how far it is in the top view from the stereo camera to your main object of interest like a character, or to about the middle point depth wise in the scene from the camera's point of view.

Select the stereo camera rig's left camera in the Maya outliner. Enter the distance value you measured as the "Zero Parallax Sphere" in the Attribute Editor.

Then take your Zero Parallax Sphere and divide it by 120 and enter this resulting number in the Camera Separation attribute in the lens shader. This should get the stereoscopic effect to be in the rough "ballpark zone" that is comfortable for the viewer regardless of what scene unit size you modeled your Maya project using.

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