drawing a line with a set %

[salmonrose]

I need to draw some pipe on a profile. The pipe is set at 0.3%. I know the starting point of the pipe, what command should I use in order to set the line to 0.3% (similar to polar tracking which you can set 15° for example).

 

Thanks.

[BIGAL]

Draw a line 333.3333 units long raise 1 end 1 unit

 

ie 1/(0.3/100)

 

If it has a vertical scale then you need to adjust the vertical 1 units to suit the horizontal ratio.

[PS_Port]

I would do similar to BIGAL except, 1000 long raise 3.

 

side note - 0.3% thats pretty flat, can they contruct/lay to that accuracy without flat spots.

[lpseifert]

try this

;;;draws a pline at a user designated %  LPS 2009-01
(defun c:pb% (/ % oldsnang oldortho oldecho)
(setq % (getreal "\nEnter percent slope: + /-: ")
     oldsnang (getvar "snapang")
     oldortho (getvar "orthomode")
     oldecho (getvar "cmdecho"))
 (setvar "cmdecho" 0)
(setvar "snapang" (atan (/ % 100)))
(setvar "orthomode" 1)
(command "pline" pause pause "")
(setvar "snapang" oldsnang)
(setvar "orthomode" oldortho)
(setvar "cmdecho" oldecho)      
(princ)
)

If you're drawing at an exaggerated scale, I've got one for that too.

[salmonrose]

I would do similar to BIGAL except, 1000 long raise 3.

 

side note - 0.3% thats pretty flat, can they contruct/lay to that accuracy without flat spots.

 

I guess they can. The existing section is 43m long @0.4%. Mine will be 70m @0.3%, then 62m @0.4%.

 

try this

;;;draws a pline at a user designated %  LPS 2009-01
(defun c:pb% (/ % oldsnang oldortho oldecho)
(setq % (getreal "\nEnter percent slope: + /-: ")
     oldsnang (getvar "snapang")
     oldortho (getvar "orthomode")
     oldecho (getvar "cmdecho"))
 (setvar "cmdecho" 0)
(setvar "snapang" (atan (/ % 100)))
(setvar "orthomode" 1)
(command "pline" pause pause "")
(setvar "snapang" oldsnang)
(setvar "orthomode" oldortho)
(setvar "cmdecho" oldecho)      
(princ)
)

If you're drawing at an exaggerated scale, I've got one for that too.

 

How do I use the above? I have never written any code before. Thanks.

[ScribbleJ]

Start the line where you're beginnig is then when prompted to (Specify next point or [undo]: enter the following. @100,0.003 - That is if it is actually a 0.3% slope which means it will rise or fall 0.003 feet in 100 feet.

 

Edit:

Oops had to edit my math.

[lpseifert]

How do I use the above? I have never written any code before. Thanks.

Have a look here

http://www.cadtutor.net/faq/questions/28/How+do+I+use+an+AutoLISP+routine%3F

 

one other alternative is to add an Additional Angle in the settings of Polar Tracking

0.3%= 0.17189 degrees (atan of 0.003)