Aspect Ratios

Intro

The aspect ratio of a Surface is determined by several factors including, the Immersive Manager Settings that the scene was set up with and the Runtime Settings that were provided when launching the experience.

Rendered Aspect Ratio vs Output Aspect Ratio

  • How a surface appears is determined by the Rendered Aspect Ratio and the Output Aspect Ratio.
  • The Output Aspect Ratio is the Aspect Ratio of the rectangle on the screen that the Surface is output to.
  • The Rendered Aspect Ratio is the Aspect Ratio of the the view into the scene that is actually rendered.
  • These will often match however they don't have to.
  • Examples:
    • Left: Output Aspect Ratio = 1.6 (eg. 16x10), Rendered Aspect Ratio = 1.6
    • Centre: Output Aspect Ratio = 1.6, Rendered Aspect Ratio = 2.0
    • Right: Output Aspect Ratio = 2.0, Rendered Aspect Ratio = 1.6

image

  • Note: Left and Centre surfaces are the same size, however the rendered aspect ratio are different.
  • Note: The Left Right surfaces are different sizes however the "content" they are rendering is the same, just stretched.

Why?

  1. When creating an experience it can be useful to know that everyone will see the exact same view into the scene. To achieve this we can use the same Rendered Aspect Ratio even when the Output Aspect Ratio need to changed due to changes in the physical characteristics of the room.
  2. Due to warping of the projects to make them fit a given room, the resolutions of the surfaces used in windows may not exactly match the aspect ratio of the physical surface. This can lead to the view appearing "compressed" or "stretched" with artifacts such as circles appear as ovals. Adjusting the Rendered Aspect Ratio can correct for these issues.

Settings

Immersive Manager Settings

  • Aspect Ratio Type: Fixed, Dynamic or FixedWithDynamicFloor.
    • This setting determines whether surfaces should adjust their aspect ratios of whether they should be fixed to ensure consistency of content.
    • Using FixedWithDynamicFloor is useful in cases where the walls require consistency of content however the floor can act dynamically.
    • If you wish to develop experiences that work across all room shapes and sizes, use a Fixed Aspect Ratio Type and follow the CAG Guidelines.
  • Standard Camera Aspect Ratio: 16x9, 16x10, 4x3
    • The Rendered Aspect Ratio of a "Standard" surface when using a Fixed Aspect Ratio Type.
    • Only applies to surfaces with Fixed Aspect Ratios.
    • If the surface is "Wide" then the Aspect Ratio will be double width of the Standard Camera Aspect Ratio.
  • Custom Aspect Ratios
    • If you are developing an experience with one particular Immersive Space in mind, you can setup specific Rendered Aspects Ratios for each surface to match the space.
    • In this case the Runtime settings will be ignored.
    • This is the least flexible option and only recommended if you are only going to run your experience in one space.
    • In most cases it is recommended to use a Dynamic Aspect Ratio instead.

Runtime Settings

  • Surface Rects:
    • Surface Rects determine the Output Aspect Ratio of each surface.
    • "-surfaces=" parameter.
    • The parameter values should be an array of "Rects" (one per surface), defining the x and y coordinates and the width and height that each surface should be rendered at relative the the windows coordinate system.
    • Eg. [0,0,1920,1080][1920,0,1920,1080][3840,0,1920,1080]
  • Physical Aspect Ratios:
    • An optional parameter that will provides the physical aspect ratio of the surface in the the Immersive Space.
    • If not provided, then the Surface Rects will be used to calculate the physical aspect ratio as a fallback.
    • This should be measured by hand.
    • "-physicalAspectRatios=" parameter.
    • The param
    • Eg. 1.5,1.76,1.3
  • Force Dynamic Aspect Ratio.
    • In certain cases an experience or scene will have been built with Fixed Aspect Ratio in mind however the end user may have a desire to run it Dynamically.
    • This option allows you to force surfaces to run with a dynamic aspect ratio.
    • WARNING: This can result in content appear incorrectly and functionality may not work perfectly.
    • "-forceDynamicWallAspectRatio=" and "-forceDynamicFloorAspectRatio="
    • Values should be true or false.

If a given surface has Dynamic Aspect Ratio Type, then the Physical Aspect Ratio will be used as the Rendered Aspect Ratio.