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Break Lines Again

#1
(This post was last modified: 05-05-2019, 07:10 PM by KevinD.)

Hi all,

I'm setting up the existing features of a site I'm working on (Outline. Contours, points and breaks). I note that it appears to me that the option to create break lines "at crossings" has been taken out of the program and now the only options are to add them from a file or manually. The manual option is straightforward enough, although I note that if you don't add more than 2 points the triangulation will ignore them.

My problem with the use of breaks is this:

On my large site plan I have a 4 existing large buildings which are all complete to at least their ground floor level and I know what those ground floor levels are (FFL ranges from 9.45 to 11.80), plus a lot of other 'physical' features (e.g. transformer vaults and concrete pads) from the previous contract.

I have lots of contours and elevation points to work with (in fact the site is relatively flat, having been partially leveled under an earlier contract). However, what I don't know (for any of the buildings or other features) is the actual ground level at the point where ground meets the building/feature. All the surveyor has given me is the FFL or the level on top of the feature (and some of these features are raised well above GL).

And so my questions are:
  1. when creating a line break do I use the GL at the point where the ground meets the feature or the level of the 'feature' itself (e.g. the FFL, the top of the transformer vault, top of kerb etc)?
  2. if I have to use the ground level when creating a break, but I don't know what the GL is at that point (even though I know the level of the 'feature'); because the software will not interpolate this level for me, what would you recommend I do?
  3. is there a case for saying I have to use two breaks? One to break based on the GL and the other for the 'feature'? - take for example the case of a raised roundabout, around which I placed a break based upon the GL at the base of the kerb. I also have one point level that defines the level of the ground for the roundabout itself. Do I just add that level to my model and let the software work things out or should I be adding a second break around the feature based upon this level?
Thanks

Kevin
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#2

Hi Kevin,

Firstly, regarding the 'break line by crossings' option; 

Yes, we removed this option in Kubla Cubed 2019, but you can still access the same functionality.  In the past we had 2 options for break lines.  You could either type the levels at the points, or you could get the levels from other lines that the break line crossed.  However, from user feedback we found a couple of issues with this:

1) It was a somewhat needless and laborious step to choose between these 2 options before drawing each line
2) Often users wanted to define some point levels, but also take the levels from other lines where the break line crossed them.  This was possible previously since the validator would offer to take levels from crossings when you clicked 'ok' or 'apply'.  However, this method was somewhat hidden to the user and we often had to explain this.

For these reasons we decided from Kubla Cubed 2019 to assume that the user would always want the levels taken from crossing lines wherever a break line crosses another line, rather than offering this later as an option in the validator.  This meant we did not need to offer two options at the start.  It makes it a lot quicker to define break lines, since you just put in levels where you want to, and leave them blank otherwise.  The logic used to set the missing levels is explained in the help file, but basically it sets the crossing levels first, and then interpolates any levels that are missing between the typed levels (if any) and the crossing levels.  The validator will require that a break line has at least 2 levels defined, which can either be by the user typing the point level, or by crossing another line with defined levels.  If this isn't the case the validator will notify you that the break line will be ignored.

So to cut a very long story short, you can do the previous 'break lines by crossings' option by drawing a break line which crosses at least 2 other lines, without defining any point levels.

Regarding the break line definition where you have platforms for buildings, etc.

There are a couple of options that are commonly used for this situation:

1) Using double lines, as you describe, with one for the ground levels, and one just beside it for the platform level.  People often use a contour for the platform area, since it's usually flat.
2) The other option is to use the feature surface element only for defining the ground levels, and then add a platform element on top of the feature surface to define the platform levels.  This allows you to utilise our side slope code and makes for a very clean ground model, so I'd probably recommend this as the best approach.

Hope this helps,

Leo
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