Subdivision, Ambient Occlusion, and Anti-Aliasing in the Hydra Viewer

Subdivision

The Hydra Viewer provides three levels of subdivsion (0, 1, 2) for the geometry on display.

Using Subdivision in the Hydra Viewer

1.   Select the geometry using the scene graph or viewer.
2.   In the Viewer (Hydra) tab, Open Edit > Set Subdivision Level
3.   Select the subdivision level.
4.   Alternatively use the shortcut keys 0, 1, and 2 to set the subdivision level.
5.   You can also check the active subdivision level by selecting an object and opening the menu.

Cubes at various levels of subdivision.

Ambient Occlusion

The Hydra Viewer lets you control how much ambient occlusion is applied to the scene in the viewer to simulate soft shadows in the cracks and crevices of the objects.

Controlling Ambient Occlusion in the Hydra Viewer

There are two preference settings for controlling ambient occlusion:

  • Ambient Occlusion Radius
  • Ambient Occlusion Sample Count
6.   Open the View menu and check Ambient Occlusion. This activates ambient occlusion.
7.   Open File > Preferences and select hydraViewer from the list.
8.   Edit ambientOcclusionRadius or ambientOcclusionSampleCount to modify the ambient occlusion.

Note:   To edit the paremeter, either edit the value or click on the parameter name and drag left and right to alter decrease/increase.

Anti-Aliasing in the Hydra Viewer

The Hydra Viewer offers four levels of Multi-Sample Antialsing. For more information see Specific Viewer Behavior.

The OpenGL driver for the graphics card returns a value for GL_MAX_SAMPLES. This value indicates the maximum supported number of samples for multi-sampling you can have.

To adjust the MSAA, select Edit > Preferences and click hydraViewer, adjust the antiAliasing setting:

Full - the full value of the maximum number of supported samples.

Medium - half the value of the maximum number of supported number of samples.

Low - quarter of the value of maximum number of samples

Off - MSAA is disabled.

Note:  When you open a new Viewer (Hydra) tab, the number of samples in use for MSAA is reported on the Katana console.