INSTRUCTIONS FOR RAY TRACING SOFTWARE: The software was conceptualised by Gregers Reimann and Tang Chee Khoay. The programming in Lisp for use in AutoCad was done by Tang Chee Khoay. >>>> >>>> >>>> 1. Load the light reflection software file by going into the >>>> following menues: Tools -> Load application -> and then chose >>>> the reflection file. >>>> 2. Draw/import the daylighting system in autocad. The daylighting >>>> system must be 2D, so all lines are in the same plane. >>>> 3. If any of the reflecting surfaces is defined as an arc it must >>>> be split into small segments for flat lines. This can be done by >>>> typing the function name "cx" in the command line and follow >>>> the instructions. >>>> 4. In order to specify which surfaces are reflectors type "dfl" >>>> in the command line and follow the instructions. NB. The >>>> reflector lines will turn into green colour. >>>> 5. In order to specify which surfaces will count the amount of rays >>>> at their final destination type "ctline" (counter line) in the >>>> command line and follow the instructions. NB. The counter lines >>>> will turn into blue colour. >>>> 6. If the counter line (ctline) should be blocked by rays coming from >>>> one side (e.g. outdoors) the function "blk" is used. This function >>>> creates a parallel blocking line to the line selected with the mouse. >>>> 7. The "pvry" (pivot ray) command allows the user to specify a >>>> point around which a fixed stretch of parallel lines of equal >>>> spacing and equal quantity will be emitted for any desired angle >>>> interval. For example, if one wants to analyse the light >>>> penetration through a vertical window at different angles the >>>> following steps should be taken: >>>> a) Draw a line that covers the entire window >>>> b) Type the command "pvry" >>>> c) Select the line drawn under point a) >>>> d) Select the pivot point of the line, which typically would be >>>> the top point of the line, which is attached at the upper window >>>> frame >>>> e) Select which side of the window is inside >>>> f) Select the start angle of the rays. This would typically be 0 >>>> deg, i.e. horizontal rays >>>> g) Select the end angle of the rays. For a vertical facade this >>>> would be 90 degress. >>>> h) Select the step interval (in degrees) for rotation around the >>>> pivot piont. At each step interval parallel rays to the line >>>> will be emitted. >>>> i) Select the number of rays that will be emitted perpendicular >>>> to the line at each step interval. The rays are equally >>>> distributed along the line and are always perpendicular to the >>>> line at each step interval. >>>> j) Select whether to pause after each step interval >>>> k) Select whether to leave or delete the rays for each step >>>> interval. >>>> >>>> Once the ray generation is completed the percentage of >>>> rays reaching the counter line (ctline) will be stated for each >>>> step interval on the screen. This information will also be >>>> generated as a text file on this path for easy import and >>>> analysis in Excel: >>>> >>>> C:\cklisp_output >>>> >>>> Other commands: >>>> >>>> * In order to specify the two point between which the light rays >>>> will be projected type "ry" (rays) in the command line and >>>> follow the instructions. A ray angle of 0 degrees means that the >>>> rays come horizontally from right to left. Increasing ray angles >>>> mean that the rays are rotated anti-clock wise. For example, a >>>> ray angle of 90 means that the rays are coming down vertically. >>>> The ray distance means the distance in mm between the rays. >>>> * In order to start the automatic reflection process type >>>> "rytrace" in the command line. The rays will automatically be >>>> reflected until they meet there final destination. A maximum >>>> number of reflections has been set to avoid perpetual circular >>>> reflection to occur in which case the software never would >>>> finish the computation. Once done with all the reflections the >>>> software computes the percentage of the initial rays that has >>>> reached the counter lines. This percentage number can be >>>> inserted on the desired location in the drawing by using the >>>> mouse.