vba equivalent for vlax-curve-getClosestPointTo ? - to measure perpendicular distance

[DS-precast]

Hello All

 

I'm trying to write a vba routine which allows me to get the starting width and length of a polyline shape by specifying three points. The polyline will usually be made up of orthographic straight lines (but not always)

 

Points 1 and 2 are the start and end points of the first side, from which I get the starting width and angle of the first side. Point 3 is a point anywhere on the opposite side. The length of the bay is the perpendicular distance between Point 3 and the first side (a line joining Points 1 & 2).

 

I have written a (crude) LISP routine using vlax-curve-getClosestPointTo, but I now would like to write a vba routine to achieve the same thing.

 

The purpose of the routine is to assist in the production of pre-cast floor layout drawings. The polyline shape would be a bay in a building drawing; the width would provide the pre-cast beam length; the length would provide the length of flooring to fill.

 

Can anybody please help or point me in the right direction?

 

Many thanks

 

 

 

;; dtr - degrees to radians
;; rtd - radians to degrees

(defun dtr (a)
 (* pi (/ a 180.0))
)

(defun rtd (a)
 (/ (* a 180.0 pi))
)

(defun C:bay (/ pt1 pt2 pt3 pt4)
 (setq OrigCmdEcho (getvar "CMDECHO")); gets CMDECHO value
 (setvar "CMDECHO" 0); sets to 0 - wont echo on command line
 (vl-load-com)
 (setq pt1 (getpoint "\Enter Point 1 : "))
 (setq pt2 (getpoint pt1 "\nEnter point 2 : "))
 (setq myline (command "_line" pt1 pt2 ""));draws 1st line
 (setq mylinename (entlast));obtain entity name of myline
 (setq pt3 (getpoint pt2 "\nEnter Point 3 : ")); get point on opposite side of rectangle
 (setq Span (distance pt1 pt2)); sets Span = length of myline
 (setq ang1 (angle pt1 pt2)); sets ang1 equal to line angle
 (setq mylinenamevla (vlax-ename->vla-object mylinename)); converts to vla object
 (setq pt4 (vlax-curve-getClosestPointTo mylinenamevla pt3 T)); gets perpendicular point
 (setq perpline (command "_line" pt3 pt4 "")); draws perpendicular line
 (setq perplinename (entlast));obtain entity name of perpline
 (setq bayl (distance pt3 pt4)); sets bay length to length of perpline
 (princ "\nSpan is : ")(princ Span)
 (princ "\nBay length is : ")(princ bayl)
 (command "_erase" mylinename "")
 (command "_erase" perplinename "")
 (setvar "CMDECHO" OrigCmdEcho); puts back to original value
 (princ)
)

[BIGAL]

I ran the code and not sure where your headed me for precast stuff I would just make a lisp for each basic shape ask L X W etc point to put it at, then you get stuff like its properties using Region & Massprop this gives stuff you need like centroid and area. The codes a bit long winded for a plain rectang. Even drawn on an angle.

 

Pretty sure theirs some tilt panel stuff here on Cadtutor search for it.

 

----------------   REGIONS   ----------------
Area:                    11871.234
Perimeter:               549.003
Bounding box:         X: 291.749  --  467.573
                     Y: 191.899  --  340.565
Centroid:             X: 383.674
                     Y: 257.132
Moments of inertia:   X: 794650878.004
                     Y: 1770166566.666
Product of inertia:  XY: 1174021820.406
Radii of gyration:    X: 258.726
                     Y: 386.153
Principal moments and X-Y directions about centroid:
                     I: 9154728.825 along [0.978 0.208]
                     J: 23258071.958 along [-0.208 0.978]

[DS-precast]

Hi BIGAL, many thanks for your response.

 

Region & Massprop isn't really what I'm looking for.

 

Maybe I can re-define my problem a bit. This is intended to be a small part of a larger project written in VBA.

 

What I want to do is to click three points on the screen. These points form a triangle (if they're not in a straight line). A line between points 1 & 2 forms the 'base' of the triangle. I can extract the length and angle of the 'base' line of the triangle.

 

I then want to find the perpendicular distance from point 3, to the 'base' of the triangle (the altitude of the triangle).

 

I have achieved this in LISP using vlax-curve-GetClosestPointTo, but I am wondering if there is a similar or equivalent command in VBA.

 

In other words, how can I achieve the same result as my LISP routine, but using VBA.

 

Hope this clarifies.

[fixo]

Search on forums for Curve.cls and Vlax.cls to use vlax functions for VBA

[DS-precast]

Many thanks fixo.

 

I downloaded your file UsingVlax.dvb from another thread, and I'm sure it gives me all I need to crack this nut.

 

I have not yet encountered Class Modules in my VBA programming , so I hope it will also provide an opportunity to increase my programming abilities.

 

In the meantime, and for the benefit of other users, I managed to write some lines of code based on triangular geometry (Heron's Formula - from Wikipedia) to obtain the altitude of the triangle. It's a solution, but maybe not as elegant as it could be.

 

Thanks again.

[SEANT]

Unfortunately, I don’t have access to a system with VBA.

 

Are we talking 2D only; this Excel spreadsheet demos a fairly modest computational method. 3D compatibility would be a little more complex but still not too bad.

Bay Lenght.zip

[DS-precast]

Thanks for the reply SEANT. It is for 2d points, not 3D. Your formula provides another interesting alternative.

 

Many thanks.