Feature Line / elevation question...

[deltacoolguy]

Feature Line / elevation question...

This might be more of a "wish list" question, I don't know.

Let's say I have two known end points with two known elevations.  I want to put a feature line between the two, but there are a couple arcs involved.  I am fine with the elevations being linear.

Is there a way to draw a feature line, and have it fill in the elevations in between automatically?

Thanks.

[jmayo-EE]

Thanks James but I will admit that I like the Pipe Network tools. They save me quite a bit of drafting time which is all I really need. Like everything else in life these tools are not perfect and as I said before, I still get the job done. With Civil 3D I get the job done much faster than it was done when I was using Softdesk, Hasp (unix based civil/survey cad app) & LDD.

[JamesMaeding]

This surprises me how poeple do not immediately understand the implications of forcing PVI's and PI's (or bc/ec's) at the same locations.  A civil tool has no business forcing that.

Those PI's and PVI's are hinge points during revision. When a feature line forces a bunch of profile hinge points where there should be none, you must babysit the thing to be sure unintended grade breaks are not introduced..

Not only that, but consider what happens when you grip a feature line, and move a point in plan view.

Did you want the elevation that was at that point, to move to the new point?  Usually not.

It may be that you do want to know the elev at new horizontal point, but more likely, you wanted the old profile to be "projected" to the new horizontal location, so slopes on eiether side are mainatined as close as possible.

Have you ever noticed that grip editing a horizontal alignment does not affect the profile at all?

That is not proper behavior either. You would want the old profile points to stay where they were in plan view, and any that fell off the new alignment would be projected perp to new alignment. So yet more holes in C3D handling of civil information.

[Joe-Bouza]

You keep harping on this PVI, PI issue. How is civil3d forcing PVI and PI to match?

 Besides, why and how would anyone introduce a Feature line to interact with a PGL? When I use a FL it is ancillary to a profile that is usually interacting with a corridor.

I'd like to here more...

I do consider what happens When I move a FL grip in plan, then I wait and whatch with glee.

You obviously have a thought out concern, but I have not been able to decern what the actual problem is. I set elevations I cahnge elevations. How is this divergent of fundemental engineering practices? Please sraighten me out

[JamesMaeding]

I took a minute to annotate a screen shot of what I mean.

I opened our rough grading-3D base for a particular project, and zoomed in on a basin.

In this case, I was making what we call "3d alignments" for design already done.

Normally I don't use contours to define slopes, only top and toe.

Anyway, the toe of the basin is at one elevation, so the profile is just an elev at start and end.

If I want to edit that 3d align, I pick it and can type E to edit existing PVI's, then enter new elevations.

It only lets me enter elev's for those two PVI points, and automatically interpolates things between.

Anyone looking at my design knows immediately that the profile is two points, not a PVI at every start/end of each plan view segment.

Look at the curb returns, its one arc with 5 PVI's at delta/4 lengths.

The PVI's do not chop the arc, and the tools do not let me modify the arc as I am editing PVI elevations.

The 3d aligns know their plan and profile data, and do not mix the two when editing.

I could make the tool behave any way I wanted, but I never force a designer to deal with interpolated points they did not put there.

[Joe-Bouza]

I guess that's nice. And what if you did want PVI at point along the way. Sometimes there is a grade break in design. But honestly, I can't recall looking a a Feature line in the elevation editor and being confused about intermediate pvi's  1. Because if I'm looking at it - its because I need to edit it and any points along the way 2. The elevation editor by default only shows the pvi at grade change and if you edit in that view it update the interpolation.

So, you showed me yours and you've already seen mine. Sorry but you still have not convinced me of your original statement that civil3d is somehow divergent, if not derelict in its application of fundamental engineering principles.

[jmayo-EE]

I agree. None of this matters to a dozer driver grading a residential driveway and I would always have a profile based design for a road or large parking lot. I don't ever recall this being an issue on the maps we create. Nor do I see how a contractor or regulatory agency can identify this on civil plans.
I don't design sites wth contours. I may cleanup contours but the design is in what we build. Rds, curbs, walls, ponds.

[JamesMaeding]

So what you are saying is you switch to alignments/profiles for certain things. That agrees perfectly with what I am saying. There are really simple types of design where the PVI's do lie on the plan segment start/ends.

A straight driveway is an example. But why two tools when alignments do the job perfectly?

Two tools evolved because Autodesk relized the need for a plan view interface for editing profiles.

They also saw the need for items that knew their profile, but would not appear in prospector.

They got that part right, and it remains as a big need.

What they misunderstood was that plan view design is not different than when you draw the profile in profile view.

The problem is feature lines may represent the shape of what you want, but they have hinge points in places not designed.

I can sum this up by saying that every row that appears in the elevation editor, should allow you to set the station to anything, and delete any rows so long as there is an elevation at the start and end of the feature line.

In addition, the triangle grips in plan view should not be tied to elevations in a horizontal or vertical sense.

That statement only makes sense once you have detangled the horizontal from vertical, and most of the time the vertical elevation points will not lie on the triangles anyway once that is done.

This is how Autodesk should fix the problem:

1) Only have elevations (rows in the elevation editor) where the user has placed elevation points.

2) There must be elevation points at the start and end stations of the feature line. The tool should assign elev 0.0 by default.

3) for grips, if an elevation point (circle) falls on a triangle grip, it should show both triangle and circle, and not glue them together unless the user grips both and moves them.

4) Allow vertical curves, and warn the user when they enter VC lengths that do not fit between PVI's

5) when triangle grips are moved, the circle points are projected perp to the resulting location of plan segments.

6) make a command to convert a feature line to alignment, should you decide you want to share the item being designed.

What would you have in the end? Plan view editing of real civil alignments without anything showing in prospector until you want it to. On top of this, the grip/elevation editor interface would apply to both feature lines and alignments, killing two birds with one stone.

I do need to correct something I had misunderstood before, but it does not change anything.

When you add an elevation point to a feature line, it does not break the plan segment it lies on into two.

It adds a circle grip for the point, and it only slides along the plan segments.

thx

[Joe-Bouza]

Uncle...Uncle...Uncle....

[Neilw_05]

First off I'd like to mention another solution to the task presented in the OP. It's not necessarily any better but just an option. Layout the featureline first, ignoring the elevations altogether. Then apply the elevations to the end points and follow up by applying a constant grade between them in the elevation editor.

As to the issue raised by James, I agree there should be a way to enforce the interpolation between specific points of a featureline if that is the intent of the designer (this could be done with some type of locking mechanism in the FL properties or elevation editor within the Civil 3D paradigm). It is indeed aggravating to have to regrade a featureline every time we move a vertex, and it is especially tedious when working around objects at elevation zero. Some sort of interpolation lock would eleminate that nuisance. The principle also applies to horizontal geometry. If we draw an arc between two tangents, almost invariably we want the arc to remain tangent if any of the geometry changes.

In my mind what you are discussing is rules based geometry and/or parametric design. In that vein, what if you could lay out featurelines that store and preserve the design intent? Arcs remain tangent to lines, parallel offsets remain parallel to the parent geometry, lines stay perpendicular to other lines or arcs when they move, end points remain snapped to other lines or arcs or a fixed location and so on. What if you could also apply those rules in the Z plane as well? As in the case cited here, you could apply a fixed slope between the end points of any complex geometry and have it maintain that slope as the plan view geometry changes. Or you could snap the end points of complex geometry in profile to the existing ground, create a grade between them and have them follow the ground profile and update the grade as the plan view end points move. These are simple scenarios. It can get much more complex such as applying rules to maintain a fixed offset from the ground profile or having the end of a line or arc maintain a fixed distance and offset from the end of another line or arc.

It's sound pretty sophisticated, but it is actually already available in another product. 

[JamesMaeding]

The option you mention is part of the regular workflow for feature lines I would expect.

I'm too lazy for that though. One of the tasks I do is make 3d grading linework out of 2d base files.

I have contours and elevation callouts along anything like a slope top/toe or flowline.

In that case, the 2d pline is there from the beginning.

You pick it and turn into a feature line, and all the bc/ec's get elevation 0.  Then when I add the elevation points at callouts and contour crossings, which are never at bc/ec points, I would have to go back and reinterpolate the points at bc/ec's.

I did notice the "show grade breaks only" button, that does help with the checking/understanding tasks I mentioned.

That is a bit dangerous too though, as the hinges still exist.

As I play more with fetaure lines, it actually gets worse.

I realized there is no way to pick an elevation in plan via text or a 3d pick. That ability is like the first thing I put in our tools, and I expect the Carlson and Trimble ones have it too.

Also, there is no way to choose which elevation to edit by pick in plan.

I guess you would have to do some kind of grip edit command with a .z filter. I forget how to do that.

I would have at least expected there was a way to grip a point on a feature line, and have that row select in the editor.

I guess when I did our tools, I wanted the user to be able to do everything in plan view, without ever having to type numbers already there. I also have several other input methods, see image.

The nice thing is all the editing abilities we have work for "shared alignments" and "non-shared alignments".

Its like if C3D combined alignment and feature lines, then just had a property on the pobject that said if the item was to show in prospectoir or not.  We call it "locked" or "hooked" to shared alignment or not.

I'm just saying this because its the kind of feedback I want as a programmer. Don't just say what you don't like, suggest solutions, and show examples if already implemented.

If you look at the pic, none of my styff is new ideas. These are all needs you discover when doing plans. Some of the items are redundant if you know our tools, but i left them in for those used to particular workflows here...

[JamesMaeding]

I forgot to mention, I originally wrote our tools as an interface replacement for LDT, and then adopted to work on C3D too.

So when you place one of our "3d alignments" that is hooked to a C3D align and profile, the changes our tools make immediately change the C3D profile.

This is why I don't know the C3D interfaces that well sometimes. We use the API to gather C3D data, then use our interface to edit things, then dump the data back to C3D.

I never adopted it to work on feature lines, but looks like I need to since the adesk interface is what it is.

I can synthesize vertical curves this way, something several people have wanted from other posts.

We can also run in non-c3d mode where we have our own alignment external database(s).

As I understand it, this is what Autodesk wants us to do. Not such good news to those that do not have company programmers.

[Anonymous]

I'm having a similar problem. I using a feature line for bottom of ditch break line. I want it to transition between contours with a constant slope. Instead, it inserts an erroneous elevation between the two contours. The contours are at 1' intervals, 25'[ apart. The slope should be -4%. Instead, it's sloping from beginning elevation to inserted node at -1.33%, then sloping to end node at -21.88%. And I used the transition prompt. What gives?

[JamesMaeding]

In general, the triangles and circles in plan indicate vertical "hinge points", so you have to use the vertical grid editor to straight grade accross non-design hinge points.

It sounds like you are setting elevations (circles) and wanting it to just respect those as PVI's.

The tool does not do that of course, so you have to manage the between points.

[Neilw_05]

Also be aware of site behavior. Objects that are Site aware will influence your feature line elevations wherever they touch or cross. If your featureline is touching or crossing other featurelines, grading objects, etc. that are in the same Site, C3D will force an elevation point at the intersection which could be causing the unwanted grade breaks.

[Anonymous]

I tried to use the elevation editor, but you can not change the elevation of the feature-line-generated PI, nor the slope. Sounds like I should be using something other than a feature for a bottom of ditch break line. What would you suggest?

[JamesMaeding]

yep, that's important.

Its also something I have ignored in my comments of how I would want feature lines to work.

That ability is what I would consider very advanced, almost something I would make the user specifically say "I want this feature line to interact with these other feature lines, no matter the site".

Either way, If anyone has links handy explaining slick ways that ability can be used, I need to read up on them.

thx

[Anonymous]

I just noticed there is another feature line who's layer was turned off, running through the center of this ditch. It was used to locate a utility on the section views and is not part of the surface. Could this be affecting the elevations of my new feature line? What can I do about it?

[Jeff_M]

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@Anonymous wrote:

Could this be affecting the elevations of my new feature line? What can I do about it?

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Yes. Put it on a different Site.

[Neilw_05]

If the line is a featureline it is likely the problem. Select it, RT click and choose Move to Site. Create a new site and put it there. That will prevent the interaction. If you don't see a Move to Site option then it is not the problem.

[Anonymous]

Thanks!