Topo surface countours "Start" and "Stop" from where?

[dan537c303956]

Under site settings you provide spacing of contour lines and tell them where to start and stop. I would like to have the contours cut through whole numbers (780 rather than 780.12...).

What is the "Start" and "Stop" in reference too? If i say 0 - 1000. Thats 1000 feet from what point? and 0 feet from what point? I thought maybe it is the level, or project base point, or survey point, but none seem to be the case.

If I move the topo surface vertically I can see the topo lines moving (cutting through different places). but if I move the level, project basepoint, or survey basepoint, nothing changes.

Any ideas?

[irneb]

The Start and Stop refers to your project's origin (i.e. 0 level). To get your contours to align with some round number, you would need to adjust the Passing Trough Elevation value.
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Note this is also referencing the Project level, so you might need to adjust it to suit surveyed level. The above is using mm as units (around 1/25"), so the numbers only look huge.

[dan537c303956]

If you're saying that the "Start"/"Stop" measures from the "Project Base Point" (which is what the levels measure from), then why do the contours stay in the same spot when the Project Base Point and Level are moved as shown in this image: ?

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The only way for the contours to move is to actually move the topo surface up or down. If the contours are measuring from the project base point, then moving the base point should have the same result.

[irneb]

No, the start/stop does not affect where each contour is drawn. It only specifies: no more contours below the start and no more above the stop. The lowest contour could easily be a fraction off the start level. It's just that if a contour would be 1' below that it won't be drawn.

The setting which governs the actual placement of each contour is the "Passing Through Level" setting, top right of the dialog. See the screen capture in my 1st post.

Think of it like you do when hatching in acad, the boundaries of the hatch is like the start/stop levels, but the hatch origin is the setting out point.

[dan537c303956]

I have one level, its at 0'-0". I enter 1'-0" in the "Passing Through Level" setting. The first topo line reads 1'-1 17/32". I suppose my question now is, what is the "Passing Through Level" being measured from? If the basepoint, then why isnt the contour labeled 1'-0", and why don't the topo lines move when I move the basepoint up, which should also move up the passing through level. It seems to me that the Passing Through Level is being measured from some arbitrary and non-identifiable source.

thx for your help btw

[irneb]

As I've stated before, all of the levels on that entire "Site Settings" dialog are relative to the project base point. Not the survey point. Why this is I'm not sure, but that's it ... you don't have a choice in the matter.

So if your contour labels indicate the surveyed levels (note you can change this to project if you wish), then the contours might be on some levels other than round figures. E.g. here's 2 sets of labels - the upper is displaying mm based on my Project base point, the lower is displaying m based on the survey point.
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The way I went about it was to find out what difference my Level 0 is compared to the survey level. In this case my survey level 0 was 8345mm below my project level 0 (I obtained this by placing a survey spot elevation on the level line in a section). So to get a round figure for contours I deduct 345 from the passing through setting.

For secondary contours the start level also needs a variation. Sorry, my previous advise on this was slightly off.

Here's the Site Settings I used to get the above working:
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[dan537c303956]

I think we are talking past each other. I am saying that the "Site Settings" which determine where the countours will be drawn are NOT relative to the project base point. To observe this, look at a topo surface in section. When you select the toposurface and move it up and down the contour lines get cut through a different spot in plan (as expected). However, when you move the basepoint up/and down nothing happens; the contour lines do not cut through a different location. This tells me that the "Passing Through Level" is not measured from the project basepoint.

Now I understand that I can see how far off I am from a round number and adjust the Passing Through Elevation to get the result I'm looking for. I just thought it would be nice to understand whats really going on.

[irneb]

However, when you move the basepoint up/and down nothing happens; the contour lines do not cut through a different location.That might be why I thought it's the Project Base. I never move the project, only the survey point. My buildings are always situated as close as possible to the project base point (i.e. similar to acad's WCS 0,0,0), then I only adjust the survey points. Though I seldom move the point itself - I prefer using the Specify Coordinates at Point & Rotate True north tools.

It seems you've found that those settings are relevant to Revit's internal coordinate system. Thus both the Project base as well as the Survey base is similar to a UCS in acad (i.e. both are simply transformation points from the underlying coordinate system), just that they start off as being the same as 0,0,0.

But as you've found ... it's not much of an issue. Simply adjust the start level (for extra contours) and the passing through level for main contours to accommodate any deviations from round level contours.

[dan537c303956]

when you link a file "origin to origin" it is using a 0,0,0 on a different coordinate system from which site settings are also measuring? If I lock the basepoint upon making a new project my basepoint and "internal coordinate system 0,0,0" will be one in the same?

Thanks