Topic: Make ALL Lines PLines?

[Josh Nieman]

Why would it matter if you're offsetting a single pline segment, or a line?

It's the situations that Luis mentioned.  Not offsetting a single segment of a one segment pline, but a single segment of a 50 segment pline.

My mistake, I misunderstood your statement to read that you were angered when you offset a single segment, and it's a pline, rather than a line.... not a chain of segments.  Alrighty then!

Yea.  I was reading it before I hit the post button, and was thinking I should put an 'or' as the first word for the next line, but decided I was to lazy on a Monday morning. 

I hear that!

[CADaver]

I haven't drawn a "line" since 91'.

I haven't drawn a line OR a Pline since '99

[CADaver]

But if you control only the Linewight, the line appears as a thickness of 0 (or is it 1). You don't have a 'thick' line in your dwg.

I can make it any width I like at plotting with the CTB/STB.  If the pline has width in the file, I'm stuck with it.

We use a linewidth of .02 for all Piping in our dwgs. I then join all I can so that if I need to move the system up an inch or so in my dwg, there is much less clicking to make sure I grab the entire system.

We build 'em 3D, so you may be right.

[CADaver]

I'm embarrassed to admit it, especially amongst all of you CAD gurus, but...

I know little about what PLines are REALLY for, other than I can make a 'thick' line with them.

craigr

What they're REALLY for?? ... is what ever you want to use 'em for.

[kentium3k]

Below is what I posted in response to a similar post on one of the other newgroups.

I prefer lines for most things I draw. If I am creating something that
makes sense as one entity then I will use a pline.

I don't like plines because people still draw them with widths for
everything and then you can't control the width in other drawings when
Xrefing them in, for instance.

Lines make sense when you are needing to offset the lines and having a
single straight pline just makes no sense to me. Plines are good if you are
going to offset say a rectangle 6" to create the boundary of a wall
thickness.

Lines can be easily checked for the angle they are drawn at, plines can't.
Draw a line and a pline, list them both, what is the angle of the pline?

Length of lines can be modified with the change command, plines cannot.
Multiple lines can be brought to one point quickly with change, plines
cannot. Lines can be straightened to align with Ortho quickly with change,
plines cannot.

If I need to show the routing of tubing and I want to show a radius at each
corner then I use plines because I can fillet every corner on a pline, with
lines I have to pick over and over.

Lines have the extra grip in the middle of the line, a straight pline will
not. That extra grip comes in handy when modifying in certain situations
when using grips.

A line inherits the elevation of the object that it is snapped to. A polyline
inherits the elevation of the first point it is started at.

Start the line command, then type tan, pick an arc, notice how the line start
point will move dynamically as you move the cursor; a pline will not do that.

Use every tool in autocad properly for your situation, there are no
absolutes in using or not using plines -VS- lines, and all other commands
for that matter. Sometimes blocks are the way to go, sometimes groups,
sometimes none at all.

[Bryco]

1) lwpolies make for a smaller dwg.(Not enough to worry about but it is a plus)
2)  In a sloppy drawing with undesired 3d, lines tend to cause more havoc.(Look at the front view)
3) In a drawing with plenty of plines I see less multiples, (line on top of line on top of Line)
      this could be related to total rookies don't bother with plines.
3) On the other hand, kentium3k makes some great points.

[Dinosaur]

. . . On the other hand, kentium3k makes some great points.

Good points indeed.  Polylines can be great tools when their use is called for, but I always found them to be more an obstacle than a help when laying out linework for a subdivision.  Much of the work is offset and fillet at different distances and radii.  Fillets would not work unless EVERYTHING was a polyline and then the segments would join when that was the last thing I wanted.  Additionally, some of the course labeling routines would not recognize polyline segments.  For that application simple lines and arcs were a much better solution.

[sinc]

How about those nifty cases where Fillet decides it should join to the far end of the polyline, rather than the end near where the user is clicking, resulting in this giant loop swooping through the drawing?

And in the Civil products, "Line/Curve from End of Object" won't work on polylines.

But polylines can be useful.  Although with Civil-3D, sometimes a 3DPOLY is the one to use.

[Josh Nieman]

Although you make some good points, kentium.. many things you state about plines are very false.

[craigr]

Sadly, for those of us that had little and in some cases no official training in AutoCad, there are many commands, variables, etc. that we do not know about &/or use. - This forum helps ALOT with that.

The few classes I took in AutoCad several years ago, were very basic compared to what alot of you folks discuss. I have learned a great deal from this & the Autodesk, (to a lesser degree) forums. I also have learned alot from drawings from other companies that I have had to work on.

One problem is that like this discussion, everyone uses the tools differently for their needs. It is tough for those of us teaching ourselves NOT to learn the 'bad habits'. What a 'bad habit' is, depends on who you are talking with.

We have seen MANY disagreements on this & other discussion boards about what is the 'proper way' of setting up a drawing & how to draw it. I have found a few times, where we as a company, have been drawing wrong, (per the AutoCad community), since we started using AutoCad many years ago. These practices are tough to get changed. - Thank goodness the bosses at our company, decided to create a CAD Coordinator position, to get us all going the same direction.

As always, thanks for all of your comments. I have learned alot about plines from this discussion. Though I may be more confused than before. I didn't know there was that much to them.

craigr

[mjfarrell]

In most cases I use plines, or on a very limited basis lines.  Most of the work that I do is connected to C3D, it like to convert these objects into other things quite handily, also as a long time LDD user plines were the best choice for construction elements because of similar conversion tools.

All objects have a purpose, much like the omitted midpoint grip of the pline, however a running osnap of MID will snap to it for you.

The plines length can be properly edited using the LENGTHEN command.

To offset a single segment without programming use the snaps, and object tracking and one can draw a parallel line at the proper offset and distance very quickly.

Setting your layouts to DWT display line weights is far more sharable than adding widths to plines.

[CADaver]

... many things you state about plines are very false.

hmmm... such as...??

[Josh Nieman]

... many things you state about plines are very false.

hmmm... such as...??

...people still draw them with widths for
everything...

Lines can be easily checked for the angle they are drawn at, plines can't.


Lines can be straightened to align with Ortho quickly with change,
plines cannot.

[deegeecees]

... As always, thanks for all of your comments. I have learned alot about plines from this discussion. Though I may be more confused than before. I didn't know there was that much to them.

craigr

I had noticed a "Pandoras Box" effect unfold in this thread as well. To each his own would apply here.

[craigr]

... As always, thanks for all of your comments. I have learned alot about plines from this discussion. Though I may be more confused than before. I didn't know there was that much to them.

craigr

I had noticed a "Pandoras Box" effect unfold in this thread as well. To each his own would apply here.

THAT is the problem though - 'To each his own' makes it tough learn to do it right.

Apparently, there ISN'T a 'right way to do it'. Or, anything having to do with CAD.

craigr