AutoLISP to offset closed polyline, hatch, and delete the second polyline [C3D]
@Anonymous wrote:
.... Let's say the layer would be inner_wall, the pattern would be solid fill, the scale would be 1.0 and the color would be 250,250,250.
If it's the SOLID pattern, the hatch scale is irrelevant. I'm assuming the color is part of the Layer, and that the Layer already exists in the drawing [those can be accounted for if necessary]. Give this a try [minimally tested]:
(defun C:OI2H ; = Offset Inward by 2 drawing units, and Hatch
(/ *error* doc);;;;; ss ent obj oarea pl2)
(setq ss nil ent nil obj nil oarea nil)
(defun *error* (errmsg)
(if (not (wcmatch errmsg "Function cancelled,quit / exit abort,console break"))
(princ (strcat "\nError: " errmsg))
); if
(vla-endundomark doc)
(princ)
); defun - *error*
(vla-startundomark (setq doc (vla-get-activedocument (vlax-get-acad-object))))
(prompt "\nBuilding outline to Offset Inward and Hatch: ")
(if (setq ss (ssget "_:S+." '((0 . "LWPOLYLINE") (-4 . "&") (70 . 1)))); one, closed only
(progn ; then
(setq
obj (vlax-ename->vla-object (setq ent (ssname ss 0)))
oarea (vla-get-Area obj)
); setq
(vla-offset obj 2)
(if (> (vla-get-Area (vlax-ename->vla-object (entlast))) oarea)
(progn ; then -- went wrong way
(entdel (entlast))
(vla-offset obj -2)
); progn
); if [went wrong way -- no else; do nothing if it went right way]
(command
"_.hatch" "SOLID" ent (setq pl2 (entlast)) "" ""
"_.chprop" "_last" "" "_layer" "YourLayerName" ""
"_.erase" pl2 ""
)
); progn -- then
); if
(vla-endundomark doc)
(princ)
); defun -- C:OI2H
(vl-load-com)
(prompt "\nType OI2H to Offset Inward by 2 drawing units and Hatch.")
I also assume that no building outline will be so small that Offsetting 2 units inward will fail. If one is of a kind of shape that results in two or more new Polylines inside, you won't get the results you want, but if that's possible, that can also be accounted for.
Kent Cooper, AIA 
@Kent1Cooper wrote:....
(defun C:OI2H ; = Offset Inward by 2 drawing units, and Hatch (/ *error* doc);;;;; ss ent obj oarea pl2) (setq ss nil ent nil obj nil oarea nil) ....
Oops -- I left the part about localized variables in testing mode [don't localize, so they can be checked after running, but wipe them out at the beginning of each run]. Replace the top 3 lines with this:
(defun C:OI2H ; = Offset Inward by 2 drawing units, and Hatch (/ *error* doc ss ent obj oarea pl2)
Yes, @john.uhden, it could check for CW/CCW direction, but I imagine [without choosing one of the assorted ways of doing that] that it would be [in code required] as much work as, or possibly more than, the compare-the-resulting-area approach. Admittedly, though, it could make a noticeable difference in the time it takes if the routine were altered to do a large quantity of them at once, instead of just one at a time. If that's a possibile need, it may be worth revising.
Kent Cooper, AIA
@Anonymous wrote:
....
1. We select a closed polyline that was previously drawn and that represents the outline of a building.2. We offset the polyline 2 units inside, creating a scaled version of the original polyline within the first.
3. We hatch the area within the two polylines with a specific hatch pattern, scale, layer and color.
4. We delete the smaller, inside polyline.
....
Another approach occurs to me, again if you're talking about SOLID for the Hatch pattern. How about Offsetting the outline inward by 1 unit to be the mid-line of that thick perimeter, and then giving it a global Polyline width of 2 units? It would take considerably less memory than a Hatch pattern, and the need to delete a temporary object afterward would be eliminated.
EDIT: Like this:
(defun C:OI2 ; = Offset Inward for 2-unit-wide perimeter
(/ *error* doc ss ent obj oarea)
(defun *error* (errmsg)
(if (not (wcmatch errmsg "Function cancelled,quit / exit abort,console break"))
(princ (strcat "\nError: " errmsg))
); if
(vla-endundomark doc)
(princ)
); defun - *error*
(vla-startundomark (setq doc (vla-get-activedocument (vlax-get-acad-object))))
(prompt "\nBuilding outline to Offset Inward: ")
(if (setq ss (ssget "_:S+." '((0 . "LWPOLYLINE") (-4 . "&") (70 . 1)))); one, closed only
(progn ; then
(setq
obj (vlax-ename->vla-object (setq ent (ssname ss 0)))
oarea (vla-get-Area obj)
); setq
(vla-offset obj 1)
(if (> (vla-get-Area (vlax-ename->vla-object (entlast))) oarea)
(progn ; then -- went wrong way
(entdel (entlast))
(vla-offset obj -1)
); progn
); if [went wrong way -- no else; do nothing if it went right way]
(setq edata (entget (entlast)))
(entmod (subst '(43 . 2.0) (assoc 43 edata) edata))
(command "_.chprop" "_last" "" "_layer" "YourLayerName" "")
); progn -- then
); if
(vla-endundomark doc)
(princ)
); defun -- C:OI2
(vl-load-com)
(prompt "\nType OI2 to Offset Inward to 2-drawing-unit-wide perimeter.")
Kent Cooper, AIA
@john.uhdenIt works perfect for me (as shown below) until it asks to select another object and then no matter what i do, it decides to hatch the entire inside area rather than just my entered offset. Ideally having the option to preset the hatch and layer/color is what i'd like as it would take out a few more steps when needing to do this on numerous houses up and down a street. I currently use ANSI32 at a scale of 5. I do like how it deletes the 2nd line though!
@kaden.bedwell wrote:
... is there a way to get this to work when tracing the boundary of a building using a polyline rather than say using a rectangle? It doesn't seem to work for me on 2d polylines even though i've closed it back to the starting point. Or is there a way to code that the polyline selected will change the closed option to 'yes' rather than 'no'?
It works for me using any kind of shape, not just rectangles. When you say you've "closed it back to the starting point," did you do it by just picking again at the starting point and ending the Polyline [not truly "closed" as AutoCAD means the term], or did you use the Close option for the closing segment, to make it truly closed? If you only drew it back to the same spot, I would discourage just changing the Closed thing in Properties from 'no' to 'yes', because it will result in a zero-length closing segment between two coincident vertices, which can cause various kinds of problems with various AutoLisp routines, though it doesn't seem to be trouble for this one.
Other possibilities:
See the end of Message 6 -- could your shape be such that more than one new Polyline results from Offsetting?
Is it a "lightweight" Polyline? That is, was it drawn with the PLINETYPE System Variable set to 1 or 2, not 0? When you pick it, does the Properties palette say it's a "Polyline" [that's the "lightweight" kind that the routine was written for] or a "2D Polyline" [the "heavy" kind that it wasn't written for]?
And finally: What does "it doesn't seem to work" mean? What happens that you don't expect, or what doesn't happen that you do? Are there any messages? If you change the Closed property yourself to 'yes' first, does it work?
Kent Cooper, AIA
@kaden.bedwell wrote:
....
I just tried changing the hatch from solid to ANSI32 and it prompted me for scale and angle and then asked to select object which in turn would hatch the entire interior of the object selected. Is there any way to include a hatch other than solid ... and put the layer on a specified layer? I havent had any issues with yours hatching to the outside at all in my testing as others have mentioned above, but i do like how others deletes the offset line at the end.
....
When the pattern is SOLID, it doesn't ask for scale or rotation, so with any other pattern, answers to those prompts need to be added. Doing the command manually [starting it with (command "_.hatch") so it will use the same variety as the routine will] reveals the sequence of prompts. Try this:
(defun C:OI2H ; = Offset Inward by 2 drawing units, and Hatch
(/ *error* doc ss ent obj oarea pl2)
(defun *error* (errmsg)
(if (not (wcmatch errmsg "Function cancelled,quit / exit abort,console break"))
(princ (strcat "\nError: " errmsg))
); if
(vla-endundomark doc)
(princ)
); defun - *error*
(vla-startundomark (setq doc (vla-get-activedocument (vlax-get-acad-object))))
(prompt "\nBuilding outline to Offset Inward and Hatch: ")
(if (setq ss (ssget "_:S+." '((0 . "LWPOLYLINE") (-4 . "&") (70 . 1)))); one, closed only
(progn ; then
(setq
obj (vlax-ename->vla-object (setq ent (ssname ss 0)))
oarea (vla-get-Area obj)
); setq
(vla-offset obj 2)
(if (> (vla-get-Area (vlax-ename->vla-object (entlast))) oarea)
(progn ; then -- went wrong way
(entdel (entlast))
(vla-offset obj -2)
); progn
); if [went wrong way -- no else; do nothing if it went right way]
(command
"_.hatch" "ANSI32" 5 0 ent (setq pl2 (entlast)) "" ""
"_.chprop" "_last" "" "_layer" "YourLayerName" ""
"_.erase" pl2 ""
)
); progn -- then
); if
(vla-endundomark doc)
(princ)
); defun -- C:OI2H
(vl-load-com)Make sure you edit the "YourLayerName" to an appropriate name. If you didn't do that before, and [as one might expect] you don't have a Layer of that name, that would explain its not removing the inboard boundary -- you would have gotten a message about that. But with a valid Layer name, it does remove it.
Kent Cooper, AIA