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Old 02-25-2004, 11:42 AM
jaytee jaytee is offline
Join Date: Oct 2003
Posts: 7

In an experiment I am working on, we have objects arranged in a circle around the subject. Part of the experiment requires that the subject face certain objects while wearing the HMD but with the display turned off. We then log the VIEW_EULER coordinates to a file and later need to determine how close the subject was from looking straight at the object (the yaw is the important angle in this case)

The problem I am running into, is that the yaw angles recorded seem to wrap around, or get counted from different axes, depending on where I am. I am only looking at the yaw. Test data shows the angles of the objects starting from straight ahead and going around clockwise:

Object 1: 2 degrees
Object 2: 48
Object 3: 85
Object 4: 40 (180-40 = 140)
Object 5: 6 (180-6 = 174)
Object 6: -30 (180+30 = 210)
Object 7: -76 (180 + 76 = 256)
Object 8: -44 (360 - 44 = 316)

I hope I am making sense... I have attached the log file, which logged multiple measurements of each object.
Attached Files
File Type: txt log.ref.2-16.txt (4.7 KB, 767 views)
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Old 02-25-2004, 12:04 PM
farshizzo farshizzo is offline
WorldViz Team Member
Join Date: Mar 2003
Posts: 2,849

I've never experienced this problem before. Which version of Vizard are you running? Have you tried just retrieving VIEW_YAW:
yaw = viz.get(viz.VIEW_YAW)
Alternatively, you could manually calculate the yaw based on the look vector:
import math
look = viz.get(viz.VIEW_LOOK)
euler = math.atan2(look[0],look[2]) * (180.0/math.pi)
Hope this helps.
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