Breaklines and Surfaces

[rhdins]

I'm finally starting to make the switch from LDD to C3D. I'm creating a surface and want to add some breaklines. Specifically I'm creating a wall breakline for TBC. The help says that I can specify points to create my breakline but when it asks me to select objects it won't let me select points. I know in LDD you could select points for your line, but I can't figure it out in C3D, any help would be appreciated.

[Anonymous]

Apparently a breakline must be a line. One way is to snap a 3dpolyline to
your points, then use it as a breakline. You can use feature lines as
breaklines I am told. The only way I can use a feature line is to explode
it and then use it. I may be missing something with that, however.

Bill


wrote in message news:5271905@discussion.autodesk.com...
I'm finally starting to make the switch from LDD to C3D. I'm creating a
surface and want to add some breaklines. Specifically I'm creating a wall
breakline for TBC. The help says that I can specify points to create my
breakline but when it asks me to select objects it won't let me select
points. I know in LDD you could select points for your line, but I can't
figure it out in C3D, any help would be appreciated.

[Nrhoads]

I got this from the help file (sometimes it "helps", sometimes it doesn't) :

Types of Breaklines

Define standard, proximity, wall, and non-destructive breaklines for a TIN surface.

Standard. Defined by selecting 3D lines, grading feature lines, and 3D polylines.

Proximity. Defined by drawing or selecting a grading feature line or polyline object in the drawing within the extents of the surface boundary. The XYZ coordinates of proximity breakline vertices are determined from the surface TIN points that are in closest proximity to the corresponding vertices of the defining points or entity.

NoteTo specify breaklines from points, first convert the points into 3D or 3D polylines using the ’PN command. For more information, see Transparent Commands.

Wall. Defined using grading feature lines, 3D lines, 3D polylines, or by specifying points. A wall breakline is stored as a standard breakline, but defined differently: you provide an offset side for the entire breakline, and an elevation difference for each vertex, or for the entire breakline.

Non-destructive. Defined using grading feature lines and open or closed AutoCAD objects. A non-destructive breakline maintains the integrity of the original surface.

You can also import breaklines from ASCII FLT files into the surface definition.

The answer to your question about points for breaklines is found in the "note" above!

Hope this helps.
Nick R

[Anonymous]

wfb wrote:
> Apparently a breakline must be a line. One way is to snap a 3dpolyline to
> your points, then use it as a breakline. You can use feature lines as
> breaklines I am told. The only way I can use a feature line is to explode
> it and then use it. I may be missing something with that, however.


I draw feature lines and create surfaces from them (As breaklines)
daily. No explosion necessary.

--
Jason Hickey

Civil 3D 2007, SP1A
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