How to use HDR image as Image Based Lighting source in a RADIANCE scene?

	1)	Download IM from http://mail.tku.edu.tw/tai/pipeline/index.html
	2)	Open the image in HDRShop, save it as .hdr or .pic file
	3)	In SketchUp, make a flat polygon with the proportion of the image.
	4)	In RADIANCE, copy below, and paste. the “canvas” is the material assigned  to the polygon for painting, named “canvas” in Ecotect.

------------------------------  image mapping -------------------------------------
void plastic art_canvas
0
0
5   0.9 0.9 0.9 0 0

void colorpict art_image_data
11 clip_r clip_g clip_b pipe.hdr picture.cal pic_u pic_v -s 2 -rx 90
0
0

art_image_data alias canvas art_canvas

------------------------------  image mapping -------------------------------------
# -s means “scale” 
# -rx 90  means rotate the image to vertical
refer to RADIANCE p.119

------------------------------  procedural material -------------------------------------

void brightfunc WoodGrain_b1
4 dirt dirt.cal -s 0.008
0
1 0.15
WoodGrain_b1 brightfunc WoodGrain_b2
4 zgrain woodpat.cal -s 0.03
0
1 0.55
WoodGrain_b2 texfunc WoodGrain_tex
6 xgrain_dx ygrain_dx zgrain_dx woodtex.cal -s 0.01
0
1 0.075
WoodGrain_tex plastic floor
0
0
5 0.502 0.251 0.00 0.005 0.025

------------------------------  mapping material -------------------------------------
void brightfunc dusty
10 dirt dirt.cal -s 2 -i 1 -rx 60 -rz 0
0
1 0.15
dusty colorpict oakfloor_pat
15 red green blue oak.pic picture.cal tile_u tile_v -s 1.1667 -i 1 -rx 0 -rz 0
0
1 0.578313253
oakfloor_pat plastic floor
0
0
5 0.2 0.1 0.07 0.02 0.05