Polylines with square endings

Hy there,

I`m a newbie in AutoLISP and I have some homeworks to do, I would be grateful if anyone could help me in solving them.

One of them is: For a selected set of polylines I have to mark all the ends of the polylines with squares. The square side is given by the user.

Thank you

Maybe is just a coincidence, because I didn`t saw the thread and I don`t know if any of my colleagues joined this forum, the thing is that everyone in my class has his own homework, and we didn`t do enough laboratories to understand how things work, so if you could help me, I would be greatful.

So you are looking to do something like this?

yes, that is it only that the squares side is given by the user

Yes, there is a prompt for that. Only problem is, this site has rules against doing homework assignments for people...

I would point you in the direction of these sites:

http://www.afralisp.net/

http://www.jefferypsanders.com/autolisptut.html

http://ronleigh.info/autolisp/index.htm

And than how could we resolve this matter?

Think about how to approach such a problem, in psuedo-code:

• Prompt user for selection of Polylines (can also include lines, arcs etc) - look into ssget function, with a filter.

• Prompt for user specification of side length - look into getdist function so that the user can pick the length too.

• Iterate through the selection set and look at each entity in turn.

• Get the Start/End Points of each entity (perhaps with vlax-curve-getStartPoint / getEndPoint)

• Create a Square at the Start Point (either using a command call (think about OSnap in this case), or look into entmake(x) - perhaps use the polar function to get the location of the points of the square).

• Before making a square at the End Point, check the Start and End points aren't the same (e.g. in the case of a closed polyline) - look into the IF function, and also the equal function.

Lee

ok I will do that. Thank you for your help

You're welcome

Out of curiosity, in an AutoLISP class, do the teach the Visual LISP commands, or is it all AutoLISP?