Need a LISP routine to select lines and copy them to a block

I have ACAD 2006 but we just bought 2012. I do transmission towers and need to cut 3D planes for sections. My structural program outputs a 3d DXF file which consists of lines in 3D space. I was able to do this manually in 2006 using the 3 points from the UCS to make the UCS based on 3 selected points, then I did a filter on the properties and selected the lines that reside on the new plane but I had trouble getting the start and endpoints for the lines manually with the filter. I can't seem to find out how to do the filter in 2012 so I thought a LISP routine would do the trick.

What I need is to be able to select 3 points on my 3D model (all lines no solids at all and no text), filter through the lines and select only those that have a start Z coordinate and an end Z coordinate equal to zero (so that only lines that reside on my new plane are selected), then I would like to copy the selection set to a new layer, make a block out of it, save the block so I can paste it to a new drawing. I don’t want to remove the lines from the original 3D model, but they could be put on the new named layer so I could turn them off or hide them later.

After running the lisp routine, I will annotate the lines and put some dimensions on them manually. This will be used to send to a Transmission Tower detailer as a schematic telling him the angle size, number of bolts and number of holes-out in the angles.

Any help would be much appreciated. I attached a ZIP of the DXF because it was too big so you can see what I am working with.

I got some help here with a LISP routine I wrote several years ago to put numbers in circles, but my autolisp skills have deteriorated since the mid 1980's.

Thanks;

George

crossing 9x13-ng.zip

You could do it by setting the ucs then selecting all entities but only copy the ones that have a z value of 0.0

Something like need to use ssget to pick multi lines (ssget "W" ) window option then sslength for how many objects

 (setq ss (ssget "W" ) ;window option 
(setq n (sslength ss)) ; for how many objects
(repeat n 
(setq objname (ssname n))
(setq tpp1 (entget objname)))
(setq endpt1 (cdr (assoc 10 tpp1))) 
(setq zval (caddr endpt1))
(if (= zval 0.0) do something here

)

    

I tried to use a QSELECT and Filter but am not getting anywhere in selecting my plane using 3 points. I can use UCS and select 3 points and the icon goes to the point I want. When I try to select lines that lie on this new plane, I don't get the results I expected. When I select a new UCS, does ACAD transform the start and end coordinates to my new plane? When I pick a QSELECT for lines with Z=0, I don't seem to get the lines on my plane to be selected.

AFA the code BIGAL posted, I don't know enough lisp to make it do anything. I did add a defun to the top but then I got stuck with my plane and UCS.