Maxwell Studio LatLong Stereo
This is the Domemaster3D wiki section for the Maxwell Studio 3.2 integrated version of the LatLong Stereo shader.
The Parallax Distance control in the initial Maxwell 3.2 Beta is in a different unit scale from the Maxwell Studio scene scale.
In Maxwell Studio if the Separation control is set to 6.5 cm, you will want to have the Parallax Distance set to 3600 units in your Maxwell set up to equate to the same rendering result you would get in the traditional Maya/Domemaster3D shader settings of Camera Separation 6.5 / Parallax Distance 360.
This is due to the fact that Maxwell Studio uses meters internally and the scene translation feature in the lens shader needs to be updated to synchronize the scene units translation with the camera separation and parallax distance controls.
Near the top of the Optics section is a Lens attribute that lets you switch the current lens shader model.
For this wiki page we are focusing on the LatLong Stereo lens model that outputs an latitude longitude format stereo image that is also called an equirectangular or spherical format.
A LatLong image usually covers a 360 ° horizontal x 180 ° vertical area and is rendered to a 2:1 aspect ratio like 2048x1024 px, 3072x1536 px, 4096x2048 px, or 8192x4096 px.
The type attribute lets you choose whether the lens shader will output either the center view (which has the stereo settings disabled), or you can choose to render a left or right stereo camera view.
Controls the vertical FOV angle (in degrees) of the rendered Latitude/Longitude image.
Controls the horizontal FOV angle (in degrees) of the rendered Latitude/Longitude image.
This checkbox will flip the view horizontally.
This checkbox will flip the view vertically.
This control adjusts the distance in the scene where the depth converges in the left and right eye views.
Objects placed closer to the camera than the Zero Parallax Distance appear to come out at the audience. Objects placed further away from the camera than the Zero Parallax Distance value appear to the viewer as if they are existing beyond the physical "wall" of the screen they are viewing.
Right now in the initial Maxwell 3.2 Betas this Parallax Distance control is measured in millimeters (mm) so you should enter a starting value of 3600 units if you are using a typical 6.5 cm camera separation value.
The initial camera separation of the left and right cameras in centimeters. This value would typically be set to a number between 6 to 6.5 centimeters for a real world scale scene.
For a "Hyperstereo" effect that can make the details in the distance pop up more the separation value can be increased greatly as long as objects aren't placed to close to the camera as this would cause eye strain.
You can also reduce the cameras separation attribute and the parallax distance smaller if you are placing objects close to a scene or rendering a scene set in a tiny microscopic world.
This stereo effect is typically reduced at the pole regions using the separation map texture to remove a "swirl" artifact that would otherwise occur.
A texture attached to this control has an effect of multiplying a 0-1 range value against the current camera Separation attribute.
This texture map control is meant to be used with an RGB image that has a black to white style grayscale texture applied. The image is used to control the amount of 3D effect, and eliminate it where desired.
This topic is discussed further down on this wiki page in the Screen Space Texture Maps section.
This attribute allows you to adjust the LatLong Stereo lens shader to work with either a horizontal orientation (Zenith Mode OFF), or an upwards / vertical orientation (Zenith Mode ON) that lines up with the upright view orientation of the Fisheye Stereo shader.
You can control the stereoscopic effect seen in the Lat-Long Stereo and Fisheye Stereo shaders with the help of control texture maps.
These texture maps work in the Maxwell stereo lens shaders and are designed to use the same stereo control texture maps as the original Domemaster3D shaders do.
The stereo control texture maps are typically an RGB image (like a PNG texture) that have a black to white color in the image which represents the area of the rendered frame that will have full stereo effect or a reduced stereo effect.
The control texture maps take care of "swirly" artifacts that would occur in the pole zones during the turning "panoramic" stereo camera rendering phase that is used to make a continuous and seamless 360 degree stereo effect.
The control maps are applied by the Maxwell lens shaders using "screen space" coordinates which means they are directly mapped 1:1 with the areas in the final rendered image.
In a separation texture map pure black means no stereo effect will appear in that area, and white means the stereo effect will be at full strength. The areas of shading between pure black and white have a feathered out stereo effect to gradually reduce the stereo depth. For a LatLong stereo control map, it really is just a simple gradient that chooses where in the image you want to start fading out the stereo effect.
The sample control texture maps files that are included with the regular Domemaster3D shaders are installed to the following location:
(These texture maps can also be used with the Maxwell Stereo lens shaders too)
Domemaster3D on Windows Images
C:\Program Files\Domemaster3D\sourceimages\
or
Domemaster3D on Mac Images
/Applications/Domemaster3D/sourceimages/
or
Domemaster3D on Linux Images
opt/Domemaster3D/sourceimages/
The texture "latlong_separation_map.png" is for feathering out the stereo effect in the pole regions in a latlong rendering. The zenith or upwards sky facing pole region is at the top of the texture map, and the nadir or downwards facing pole region is on the bottom of the texture map.
To demonstrate how the LatLong Stereo shader works inside of Maxwell Render, a Maxwell Studio .mxs based version of the classic Maya/Domemaster3D CubeX scene has been prepared.
You can download this example file here:
maxwell_latlong_stereo_cubex.zip
(The left and right views were merged to red/cyan anaglyph for inline wiki based viewing)
