How do I calculate visual angles of objects in vizard?

[lklab]

I am using the DK1 Oculus rift. How can I calculate the visual angles of objects in the scene?

[Jeff]

The vizmat (http://docs.worldviz.com/vizard/#commands/vizmat/AngleBetweenVector.htm) library includes commands for calculating angles and other mathematical operations. Can you describe further what you mean by visual angles?

[lklab]

From wikipedia: "The visual angle is the angle a viewed object subtends at the eye, usually stated in degrees of arc. It also is called the object's angular size."

Heres a diagram:
https://upload.wikimedia.org/wikipedia/commons/thumb/1/19/VisualAngleAboveHorizonDefs.svg/413px-VisualAngleAboveHorizonDefs.svg.png

Basically I want to find the perceived size of an object in terms of angle occupied in the visual space. I wasn't sure how to calculate this because I don't know how vizard calculates each screen or how the oculus may distort things.

Also, is there an easy way to measure how big an object in vizard is?

[Jeff]

You can use vizmat.Distance (http://docs.worldviz.com/vizard/#commands/vizmat/Distance.htm) to calculate the distance from the viewpoint to an object and node.getBoundingBox (http://docs.worldviz.com/vizard/#commands/node3d/getBoundingBox.htm) to get the dimensions of an object.