World coordinates

The radiance Object creates a world that is always oriented the following way:

Y is North

X is East

Z is sky

(therefore, -Y is South, and -X is West. And! Ground is at Z=0).

Here is a panel that is facing South. The program creates the bottom edge of the module at the axis X = 0. The cube is for showing where (0,0) is.

For tracking systems (N-S axis), if the modules are facing East (early morning), the edge of the center row (or the row being queried) will align with the X-axis (X=0), and the linepoint or sensors will query the panel along the Y-axis (Y=0), in increasing negative values of X liek on the image below.

For this same scenario but facing West, the opposite is true (So you should expect to see X {0.1, 0.2, 0.3 .... 0.9}, meanwhile Y = 0).

How to sanity check?

1. Choose a timestamp where you know when the sun is and when DNI is high. Generate the sky, and switch the geometry azimuth to match where the sun's azimuth is (considering that North = 0). If the panels are facing the sun, the front side should give a high irradiance. If the panels are wrongly oriented, the values will not be as high. OR
2. Hack the program by adding a little box ('box.rad') in your object folder with the following code: ! genbox black PVmodule 0.5 0.5 0.5 | xform -t -0.25 -0.25 0 Call this box.rad on your Scene .rad object (also in the objects folder). Translate the box to wherever you want to check where that coordinate is. For example, to center the box on 0,0 and leave the bottom surface flat on the Z=0 plane, !xform -rz 0 objects\center.rad (Don't forget to re-run the makeOct command after adding these lines so you can use the RVU viewer).