AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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*Steve Cannon
Message 41 of 47 (64 Views)

Re: Civil3D 2005

03-15-2004 08:42 AM in reply to: *Brian Hailey
Don, > To my understanding of C3D the second > two data strings know their relationship > to one another. This is the 100 million dollar question, and the fact the Dave brought it up in this thread may reveal some background on the structure and dynamic relationship of feature lines. I believe the current data structure for a C3D feature line is such that it really is nothing more than that of a 'background' version of a 3dpolyline. It seems that all horizontal curves are represented for grading purposes as a series of short chords. It seems like Dave as asking if the same process should hold true for parabolic vertical curves. An alignment object as the primary feature line should retain its object properties, including 'true' horizontal and vertical geometry, while at the same time be able to control a grading attached to it. But what about the secondary feature line (created from the primary feature line) in a grading group and the grading it controls? It seems like it is defined only by the 'short-chorded' approximation of the primary alignment, and therefore the accuracy of any grading created from it would be based solely upon the accuracy of the short-chorded definition of the primary alignment. sc
*Doug Boys
Message 42 of 47 (64 Views)

Re: Civil3D 2005

03-16-2004 01:42 AM in reply to: *Brian Hailey
If an Alignment Object is created as a secondary feature dependent on another object then it should be created with proper horizontal geometry and vertical geometry which is either; a direct "offset" from the primary object (if that object is an Alignment Object also); or is the best approximation to the primary object if the primary object is just an ordinary 3D polyline etc. If the object being created is defined or chosen to be a 3D polyline then short chords will be OK. It depends on what each object is defined as. (Somebody has to define the logical structure of all this first. I had hoped Autodesk would do this.) The MX package has a function which can recreate horizontal and vertical geometry from a 3D "chorded string". Land Desktop should include a similar function. Doug Boys "Steve Cannon" wrote in message news:4055dd0c_3@newsprd01... > Don, > > > To my understanding of C3D the second > > two data strings know their relationship > > to one another. > > This is the 100 million dollar question, and the fact the Dave brought it up > in this thread may reveal some background on the structure and dynamic > relationship of feature lines. I believe the current data structure for a > C3D feature line is such that it really is nothing more than that of a > 'background' version of a 3dpolyline. It seems that all horizontal curves > are represented for grading purposes as a series of short chords. It seems > like Dave as asking if the same process should hold true for parabolic > vertical curves. An alignment object as the primary feature line should > retain its object properties, including 'true' horizontal and vertical > geometry, while at the same time be able to control a grading attached to > it. But what about the secondary feature line (created from the primary > feature line) in a grading group and the grading it controls? It seems like > it is defined only by the 'short-chorded' approximation of the primary > alignment, and therefore the accuracy of any grading created from it would > be based solely upon the accuracy of the short-chorded definition of the > primary alignment. > > sc > >
*Doug Boys
Message 43 of 47 (64 Views)

Re: Civil3D 2005

03-16-2004 01:46 AM in reply to: *Brian Hailey
OK That would be an acceptable starting point. Maybe the concept would be refined later to attach those properties to individual objects. Doug Boys "Steve Cannon" wrote in message news:4055dcec$1_2@newsprd01... > Doug, > > operators are just simple civil engineers. What about one overall C3D setup > option where the user presets the desired horizontal and vertical design > tolerance. Let internal background algorithms determine the sampling > intervals that will deliver that tolerance throughout the product.
*Glen Albert
Message 44 of 47 (64 Views)

Re: Civil3D 2005

03-16-2004 06:33 AM in reply to: *Brian Hailey
Steve, The feature line is more like an alignment then a 3D Polyline. It has a horizontal geometry definition of lines and/or arcs. On top of that is has an elevational component. When we grade from it we do create a true curved surface. Tesselation comes into play when we create a surface from the grading or when grading is shaded, as they both require faces, or with explode. Glen "Steve Cannon" wrote in message news:4055dd0c_3@newsprd01... > Don, > > > To my understanding of C3D the second > > two data strings know their relationship > > to one another. > > This is the 100 million dollar question, and the fact the Dave brought it up > in this thread may reveal some background on the structure and dynamic > relationship of feature lines. I believe the current data structure for a > C3D feature line is such that it really is nothing more than that of a > 'background' version of a 3dpolyline. It seems that all horizontal curves > are represented for grading purposes as a series of short chords. It seems > like Dave as asking if the same process should hold true for parabolic > vertical curves. An alignment object as the primary feature line should > retain its object properties, including 'true' horizontal and vertical > geometry, while at the same time be able to control a grading attached to > it. But what about the secondary feature line (created from the primary > feature line) in a grading group and the grading it controls? It seems like > it is defined only by the 'short-chorded' approximation of the primary > alignment, and therefore the accuracy of any grading created from it would > be based solely upon the accuracy of the short-chorded definition of the > primary alignment. > > sc > >
*Steve Cannon
Message 45 of 47 (64 Views)

Re: Civil3D 2005

03-16-2004 06:48 AM in reply to: *Brian Hailey
Glen, That is good news! This means it should be pretty easy for Manchester to tie gradings to alignments! Should we see this in the next C3D release? sc "Glen Albert" wrote in message news:4057100a_2@newsprd01... > Steve, > > The feature line is more like an alignment then a 3D Polyline. It has a > horizontal geometry definition of lines and/or arcs. On top of that is has > an elevational component. When we grade from it we do create a true curved > surface. Tesselation comes into play when we create a surface from the > grading or when grading is shaded, as they both require faces, or with > explode. > > Glen
*Glen Albert
Message 46 of 47 (64 Views)

Re: Civil3D 2005

03-16-2004 09:07 AM in reply to: *Brian Hailey
Steve, Being in development I can't speak on when features will be released, but we are going to support grading from alignments. It will be up to Dave as to when the features of the next release can be announced. Alignments do have more complexity then feature lines - with vertical curves, spirals, multiple vertical alignments, vertical alignemnts that don't run the entire length of the alignment. Glen "Steve Cannon" wrote in message news:405713ac$1_1@newsprd01... > Glen, > > That is good news! This means it should be pretty easy for Manchester to > tie gradings to alignments! Should we see this in the next C3D release? > > sc
*Don Reichle
Message 47 of 47 (64 Views)

Re: Civil3D 2005

03-16-2004 09:39 AM in reply to: *Brian Hailey
So with all the restrictions to speaking of particulars in place... Is it a safe assumption on my part that something like what I dreamed up would be possible in the near future? Snip>OK, following your hypothetical illustration; Knowns: Lot Corner Point Horizontal Alignment Vertical Alignment To my understanding of C3D the second two data strings know their relationship to one another. The first data bit can be assigned a relationship to the two strings through the magic of Label Styles. I haven't heard specifically, but can we assume that the folks in NH are wise enough to include a function that would add/subtract a user-supplied amount from the Z value produced at a certain station (that station calculated by said Label Style relationship on the Point) on said alignment data string relationship, and then apply that Z offset calculation as the Z coordinate value at said Point? -- Don Reichle "King of Work-Arounds" Ifland Engineers, Inc. "Glen Albert" wrote in message news:40573441$1_3@newsprd01... > Steve, > > Being in development I can't speak on when features will be released, but we > are going to support grading from alignments. It will be up to Dave as to > when the features of the next release can be announced. > > Alignments do have more complexity then feature lines - with vertical > curves, spirals, multiple vertical alignments, vertical alignemnts that > don't run the entire length of the alignment. > > Glen > > "Steve Cannon" wrote in message > news:405713ac$1_1@newsprd01... > > Glen, > > > > That is good news! This means it should be pretty easy for Manchester to > > tie gradings to alignments! Should we see this in the next C3D release? > > > > sc > >
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