topic Re: in ObjectARX Forum

Is there LWPolyline in 3D?

Anonymous — Tue, 12 Aug 2003 07:41:41 GMT

I want to draw lines with each endpoints defined in 3D Coordinate. Is my
option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't need
curve fittings stuff etc, with the lines.
In ObjectArx help, it is stated (not exact words) that AcDbPolyline
(LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is there a more
efficient cousin of AcDb3dPolyline?

Joseph

Re: Is there LWPolyline in 3D?

Anonymous — Tue, 12 Aug 2003 08:21:01 GMT

If you want a non-planar polyline, then AcDb3dPolyline is your only choice.
AcDb3dPolyline is the only polyline that can be non-planar. There is no
"more efficient cousin" for AcDb3dPolyline.

"Joseph Pods" wrote in message
news:6EBC18EBFFE2B8BA26F455A4100D44E8@in.WebX.maYIadrTaRb...
> I want to draw lines with each endpoints defined in 3D Coordinate. Is my
> option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't need
> curve fittings stuff etc, with the lines.
> In ObjectArx help, it is stated (not exact words) that AcDbPolyline
> (LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is there a
more
> efficient cousin of AcDb3dPolyline?
>
> Joseph
>
>

Re:

Anonymous — Tue, 12 Aug 2003 09:13:31 GMT

Art,
Actually I just need one straight line from startPoint to the endPoint,
but it must be in 3DSpace. Can I just use AcDbPolyline and then use
transformation matrix to rotate it to the correct attitude in 3DSpace, I
need to write more code though.

Btw, when AutoDesk says more efficient, do you know what they meant? More
efficient in memory usage, drawing the graphics etc ? I need to consider if
it worths the time to write more code than to just use AcDb3dPolyline

Joseph

"Art Cooney" wrote in message
news:9DCF4A7314EBD880CDCDB853612CAB99@in.WebX.maYIadrTaRb...
> If you want a non-planar polyline, then AcDb3dPolyline is your only
choice.
> AcDb3dPolyline is the only polyline that can be non-planar. There is no
> "more efficient cousin" for AcDb3dPolyline.
>
> "Joseph Pods" wrote in message
> news:6EBC18EBFFE2B8BA26F455A4100D44E8@in.WebX.maYIadrTaRb...
> > I want to draw lines with each endpoints defined in 3D Coordinate. Is my
> > option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't need
> > curve fittings stuff etc, with the lines.
> > In ObjectArx help, it is stated (not exact words) that AcDbPolyline
> > (LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is there a
> more
> > efficient cousin of AcDb3dPolyline?
> >
> > Joseph
> >
> >
>
>

Re:

Anonymous — Tue, 12 Aug 2003 09:29:27 GMT

how about AcDbLine then?

"Joseph Pods" wrote in message
news:7A7DD8B8947C41AE2DD39614F4382CA5@in.WebX.maYIadrTaRb...
> Art,
> Actually I just need one straight line from startPoint to the
endPoint,
> but it must be in 3DSpace. Can I just use AcDbPolyline and then use
> transformation matrix to rotate it to the correct attitude in 3DSpace, I
> need to write more code though.
>
> Btw, when AutoDesk says more efficient, do you know what they meant? More
> efficient in memory usage, drawing the graphics etc ? I need to consider
if
> it worths the time to write more code than to just use AcDb3dPolyline
>
> Joseph
>
>
> "Art Cooney" wrote in message
> news:9DCF4A7314EBD880CDCDB853612CAB99@in.WebX.maYIadrTaRb...
> > If you want a non-planar polyline, then AcDb3dPolyline is your only
> choice.
> > AcDb3dPolyline is the only polyline that can be non-planar. There is no
> > "more efficient cousin" for AcDb3dPolyline.
> >
> > "Joseph Pods" wrote in message
> > news:6EBC18EBFFE2B8BA26F455A4100D44E8@in.WebX.maYIadrTaRb...
> > > I want to draw lines with each endpoints defined in 3D Coordinate. Is
my
> > > option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't
need
> > > curve fittings stuff etc, with the lines.
> > > In ObjectArx help, it is stated (not exact words) that AcDbPolyline
> > > (LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is there
a
> > more
> > > efficient cousin of AcDb3dPolyline?
> > >
> > > Joseph
> > >
> > >
> >
> >
>
>

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Re:

Anonymous — Tue, 12 Aug 2003 09:35:58 GMT

Joseph,

Polyline will prevent you to store redundant points when you need to draw
line connected segments. This will speed up several AutoCAD features and
save DWG store space.

For instance, if you need 4 segments:
AcDbLine: 4 X 2 points = 8 points
AcDbPolyline: 1+1+1+1+1 = 5 points

For 10 segments:
AcDbLine: 10 X 2 points = 20 points
AcDbPolyline: (n+1) = 10+1 = 11 points

For 100 segments:
AcDbLine: 100 X 2 points = 200 points
AcDbPolyline: (n+1) = 100+1 = 101 points

So, if your number of segments is too small there is no big deal to use
polylines instead of lines (in your case where you will not need to curve,
fit, etc.).
If the number of segments will be huge, so the advantage is really great and
you should use polylines.

Regards,
Fernando.

"Joseph Pods" wrote in message
news:7A7DD8B8947C41AE2DD39614F4382CA5@in.WebX.maYIadrTaRb...
> Art,
> Actually I just need one straight line from startPoint to the
endPoint,
> but it must be in 3DSpace. Can I just use AcDbPolyline and then use
> transformation matrix to rotate it to the correct attitude in 3DSpace, I
> need to write more code though.
>
> Btw, when AutoDesk says more efficient, do you know what they meant? More
> efficient in memory usage, drawing the graphics etc ? I need to consider
if
> it worths the time to write more code than to just use AcDb3dPolyline
>
> Joseph
>
>
> "Art Cooney" wrote in message
> news:9DCF4A7314EBD880CDCDB853612CAB99@in.WebX.maYIadrTaRb...
> > If you want a non-planar polyline, then AcDb3dPolyline is your only
> choice.
> > AcDb3dPolyline is the only polyline that can be non-planar. There is no
> > "more efficient cousin" for AcDb3dPolyline.
> >
> > "Joseph Pods" wrote in message
> > news:6EBC18EBFFE2B8BA26F455A4100D44E8@in.WebX.maYIadrTaRb...
> > > I want to draw lines with each endpoints defined in 3D Coordinate. Is
my
> > > option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't
need
> > > curve fittings stuff etc, with the lines.
> > > In ObjectArx help, it is stated (not exact words) that AcDbPolyline
> > > (LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is there
a
> > more
> > > efficient cousin of AcDb3dPolyline?
> > >
> > > Joseph
> > >
> > >
> >
> >
>
>

Re:

Anonymous — Tue, 12 Aug 2003 11:54:23 GMT

If you only want a line segment, then why not use AcDbLine? It's 3d and
goes from 3d start point to 3d end point.

If you want a multisegment line that is planar, then you can use
AcDbPolyline. The line must be planar, but the plane can be any plane in 3d
space.

AcDbPolyline is more efficient in memory usage and in required storage space
in a dwg or dxf file. It is also more efficient in operations done to/with
it. But, if you only need a line segment from start point to end point,
then AcDbLine is the most efficient and easiest to use.

"Joseph Pods" wrote in message
news:7A7DD8B8947C41AE2DD39614F4382CA5@in.WebX.maYIadrTaRb...
> Art,
> Actually I just need one straight line from startPoint to the
endPoint,
> but it must be in 3DSpace. Can I just use AcDbPolyline and then use
> transformation matrix to rotate it to the correct attitude in 3DSpace, I
> need to write more code though.
>
> Btw, when AutoDesk says more efficient, do you know what they meant? More
> efficient in memory usage, drawing the graphics etc ? I need to consider
if
> it worths the time to write more code than to just use AcDb3dPolyline
>
> Joseph
>
>
> "Art Cooney" wrote in message
> news:9DCF4A7314EBD880CDCDB853612CAB99@in.WebX.maYIadrTaRb...
> > If you want a non-planar polyline, then AcDb3dPolyline is your only
> choice.
> > AcDb3dPolyline is the only polyline that can be non-planar. There is no
> > "more efficient cousin" for AcDb3dPolyline.
> >
> > "Joseph Pods" wrote in message
> > news:6EBC18EBFFE2B8BA26F455A4100D44E8@in.WebX.maYIadrTaRb...
> > > I want to draw lines with each endpoints defined in 3D Coordinate. Is
my
> > > option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't
need
> > > curve fittings stuff etc, with the lines.
> > > In ObjectArx help, it is stated (not exact words) that AcDbPolyline
> > > (LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is there
a
> > more
> > > efficient cousin of AcDb3dPolyline?
> > >
> > > Joseph
> > >
> > >
> >
> >
>
>

Re:

Anonymous — Tue, 12 Aug 2003 11:57:55 GMT

But, individual AcDbLines can be more efficient for graphics because any
lines that are not in the current display can be ignored high up in our
graphics system, whereas a single polyline must have all of it's segments
considered until you get very deep down into the graphics pipeline.

So, there are many issues to consider when deciding which way to go for
performance reasons. 🙂

"Fernando P. Malard" wrote in message
news:060047256189C34CCA7C068FF63EF8AC@in.WebX.maYIadrTaRb...
> Joseph,
>
> Polyline will prevent you to store redundant points when you need to draw
> line connected segments. This will speed up several AutoCAD features and
> save DWG store space.
>
> For instance, if you need 4 segments:
> AcDbLine: 4 X 2 points = 8 points
> AcDbPolyline: 1+1+1+1+1 = 5 points
>
> For 10 segments:
> AcDbLine: 10 X 2 points = 20 points
> AcDbPolyline: (n+1) = 10+1 = 11 points
>
> For 100 segments:
> AcDbLine: 100 X 2 points = 200 points
> AcDbPolyline: (n+1) = 100+1 = 101 points
>
> So, if your number of segments is too small there is no big deal to use
> polylines instead of lines (in your case where you will not need to curve,
> fit, etc.).
> If the number of segments will be huge, so the advantage is really great
and
> you should use polylines.
>
> Regards,
> Fernando.
>
> "Joseph Pods" wrote in message
> news:7A7DD8B8947C41AE2DD39614F4382CA5@in.WebX.maYIadrTaRb...
> > Art,
> > Actually I just need one straight line from startPoint to the
> endPoint,
> > but it must be in 3DSpace. Can I just use AcDbPolyline and then use
> > transformation matrix to rotate it to the correct attitude in 3DSpace, I
> > need to write more code though.
> >
> > Btw, when AutoDesk says more efficient, do you know what they meant?
More
> > efficient in memory usage, drawing the graphics etc ? I need to consider
> if
> > it worths the time to write more code than to just use AcDb3dPolyline
> >
> > Joseph
> >
> >
> > "Art Cooney" wrote in message
> > news:9DCF4A7314EBD880CDCDB853612CAB99@in.WebX.maYIadrTaRb...
> > > If you want a non-planar polyline, then AcDb3dPolyline is your only
> > choice.
> > > AcDb3dPolyline is the only polyline that can be non-planar. There is
no
> > > "more efficient cousin" for AcDb3dPolyline.
> > >
> > > "Joseph Pods" wrote in message
> > > news:6EBC18EBFFE2B8BA26F455A4100D44E8@in.WebX.maYIadrTaRb...
> > > > I want to draw lines with each endpoints defined in 3D Coordinate.
Is
> my
> > > > option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't
> need
> > > > curve fittings stuff etc, with the lines.
> > > > In ObjectArx help, it is stated (not exact words) that AcDbPolyline
> > > > (LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is
there
> a
> > > more
> > > > efficient cousin of AcDb3dPolyline?
> > > >
> > > > Joseph
> > > >
> > > >
> > >
> > >
> >
> >
>
>

Re:

Anonymous — Tue, 12 Aug 2003 14:53:08 GMT

I'm going to use AcDbLine.
Thanx for all the help, guys. All the explanations are extremely helpful. I
know how and when PolyLine is more efficient than AcDbLine.

Joseph

"Art Cooney" wrote in message
news:5AEA6FF2B7BE4FF58F75FF8BEB5F18E9@in.WebX.maYIadrTaRb...
> If you only want a line segment, then why not use AcDbLine? It's 3d and
> goes from 3d start point to 3d end point.
>
> If you want a multisegment line that is planar, then you can use
> AcDbPolyline. The line must be planar, but the plane can be any plane in
3d
> space.
>
> AcDbPolyline is more efficient in memory usage and in required storage
space
> in a dwg or dxf file. It is also more efficient in operations done
to/with
> it. But, if you only need a line segment from start point to end point,
> then AcDbLine is the most efficient and easiest to use.
>
> "Joseph Pods" wrote in message
> news:7A7DD8B8947C41AE2DD39614F4382CA5@in.WebX.maYIadrTaRb...
> > Art,
> > Actually I just need one straight line from startPoint to the
> endPoint,
> > but it must be in 3DSpace. Can I just use AcDbPolyline and then use
> > transformation matrix to rotate it to the correct attitude in 3DSpace, I
> > need to write more code though.
> >
> > Btw, when AutoDesk says more efficient, do you know what they meant?
More
> > efficient in memory usage, drawing the graphics etc ? I need to consider
> if
> > it worths the time to write more code than to just use AcDb3dPolyline
> >
> > Joseph
> >
> >
> > "Art Cooney" wrote in message
> > news:9DCF4A7314EBD880CDCDB853612CAB99@in.WebX.maYIadrTaRb...
> > > If you want a non-planar polyline, then AcDb3dPolyline is your only
> > choice.
> > > AcDb3dPolyline is the only polyline that can be non-planar. There is
no
> > > "more efficient cousin" for AcDb3dPolyline.
> > >
> > > "Joseph Pods" wrote in message
> > > news:6EBC18EBFFE2B8BA26F455A4100D44E8@in.WebX.maYIadrTaRb...
> > > > I want to draw lines with each endpoints defined in 3D Coordinate.
Is
> my
> > > > option only AcDb3dPolyline? I do NOT need to do fancy stuff, don't
> need
> > > > curve fittings stuff etc, with the lines.
> > > > In ObjectArx help, it is stated (not exact words) that AcDbPolyline
> > > > (LWPolyline) is the more efficient cousin of AcDb2dPolyline. Is
there
> a
> > > more
> > > > efficient cousin of AcDb3dPolyline?
> > > >
> > > > Joseph
> > > >
> > > >
> > >
> > >
> >
> >
>
>