LISPs for coordinate systems

I was wondering if it was possible to take a site plan I have and
generate a detailed coordinate list from the points on the plan. I am
new to LISPs and was wondering what would be a good was to learn them
and how to apply them as in the case that I want to use them for. any
help would be much appreciated.

 

You might want to start by brushing up on your syntax ; )

 

you would want to learn how to deal with selection sets, cycle though
each selection set entity, and extract the 3d point information. The
best way to start is to learn is by starting small. check out the
literature on DXF codes for a point and examine the command line code
below:


Here is an example. I opened an empty DWG file, and created 2
points... now I typed the follow commands on the command line and get
the following responses.

: (setq a (entnext))
<Entity name: cbb5cf8>
: (setq b (entnext a))
<Entity name: ab03c08>
: (entget a)
((-1 . <Entity name: cbb5cf8>) (0 . "POINT") (5 . "36") (67 . 0) (8 .
"0") (62 . 256) (6 . "BYLAYER") (370 . -1) (48 . 1.00000) (60 . 0) (10
8.58817 4.32759 0.000000) (39 . 0.000000) (210 0.000000 0.000000
1.00000) (50 . 0.000000))
: (entget b)
((-1 . <Entity name: ab03c08>) (0 . "POINT") (5 . "37") (67 . 0) (8 .
"0") (62 . 256) (6 . "BYLAYER") (370 . -1) (48 . 1.00000) (60 . 0) (10
8.23506 4.58804 0.000000) (39 . 0.000000) (210 0.000000 0.000000
1.00000) (50 . 0.000000))


DXF code # 10 is the point value (x,y,z)


: (cdr (assoc 10 (entget a)))
(8.58817 4.32759 0.000000)



Now you want to do this to a huge file so, looping is nessasary

steve