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Thread: Site Topo

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    Default Site Topo

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    I have already the AutoCAD topo inserts in place.

    I established my First Floor Level at 278', physically moving the First Floor label line to 278'. (The topo survey indicates 276.6' as the entry datum.) And I maintained (or tweaked to say it bluntly) the benchmark text at 0' - 0" as my 1st Floor Level (0'-0" = 278'-0"), though I don't know what the repercussion would be.

    The lot is basically flat 100' deep and 280' wide, relatively 2' gently sloping on the short side.

    And the first task was laying out the driveway which for now I want it flat and I used Toposurface/Place Points but then I noticed that it's following the topo of wherever the boundary of that driveway falls. Much like cutting a section across a mound, it stays with an undulating profile.

    And there's is a sort of little anthill in the middle of the driveway and on the driveway curb itself, and I got rid of it, I had to pepper it with lots of points (set at 1' below the Floor Level line) to remove it.

    Also, by Toposurface/Place Point, the points generated behave like ripples or waves by the beach. There's no way I can make a zigzag or branch-shaped surface.

    One thing I discovered is the opposite, deleting existing points which is done one by one only. And every time I did that, the contour lines kept on receding and straightening which I may had affected the topo outside the focus area, which should not be touched, isn't it, not the right thing to do.

    I tried using Subregion, and this is very user friendly when it comes to defining the shape of the driveway (if one can just traced what was sketched in AutoCAD) but then there is no option that will set the surface bulldozed and flat-rolled at 277'.

    The Building Pad method just conforms to my requirements, I can set the height and evenness of the surface easily but the component generated will be identified forever as a Pad not as a Pavement, not the right thing to do also.

    What is the best tecnhique to go about this task?

  2. #2
    Luminous Being tzframpton's Avatar
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    I would suggest getting familiar with Survey Point (SVP) and the Project Base Point (PBP) instead of creating Levels that are hundreds of feet above a particular datum:

    http://knowledge.autodesk.com/suppor...CE5F2-htm.html

    Use the SVP to create a "true" geographical position. Then use the PBP to establish your levels that are 0'-0" / 100'-0" / etc., based off your preference. This will create consistency with your Levels by referencing the PBP instead of the SVP. However, you can certainly create a new Level Type and have it reference the SVP if this information is ever needed within a view.

    *TIP*
    Pay special attention to CLIPPED and UNCLIPPED SVP/PBP's in the link above. They are very important to grasp and some people have a hard time acquiring the procedure. Basically, in AutoCAD, you have a hard-coded WCS that cannot be manipulated. Everything revolves around the WCS, so physically moving things relative to the WCS is always how it's been. In Revit, you choose where the "WCS" (aka Survey Point) is located - a procedure completely bass-ackwards for AutoCAD users. The Project Base Point can be seen as the UCS relative to the WCS in AutoCAD.

    Hope this helps.

    -TZ
    Tannar Z. Frampton ™ | Frampton & Associates, Inc.

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    Thanks TZ, I learned every time from you.

    Your explanation on the SVP and PBP is I think, caps all the tutorials and topics I read about this. I think I won't have any more problems with it.

    And this is the 2nd part of my query which I am explaining more with visual aid (see attached).

    All the tutorials I encountered on creating a driveway especially on an undulating site are so basic and kindergarten. They didn't consider the curbs.

    I prefer now doing the pavements on the site by Splitsurface method although they say it eats more memory - rather than the Subregion method.

    There's one video tutorial I saw that provides an option of making a flat pavement.

    First is go to Splitsurface, define the boundaries of your pavement, then select all the points, and an Elevation field will appear on the Options Bar. Input the desired elevation, then finish the sketch.

    Then after esc, esc, select the topo model (the mother topo for which the pavement was split), select Massing & Site/Toposurface and the Modify/Topography tab will appear. Select Edit Surface. Carefully select by windowing the points within and on the perimeter of the driveway surface, avoiding the unfenced points. An Elevation field will appear on the Options bar and input the same elevation figure previously entered. Finish the sketch.

    This will connect the two surfaces, with one elevation level defined between their boundaries.

    But how about making the curb? I think this will not be applicable because topo surface and pavement components behave like a mantle. A curb needs a rim top and a rim face. Splitsurface command can't create a rim face. Only an air gap between them is created.

    The last of my concern here is if Revit can shave off the unwanted portion and likewise, fill or patch up the unfilled portion of the topo defined by the curb? (see illustration attached). With that answered, I'm good to go with my site plan session. Thanks once again.
    Attached Files

  4. #4
    Luminous Being tzframpton's Avatar
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    I am not a civil background at all. Some people I know have made decent strides with Topography and such in Revit, but generally anything related to Site/Topo/Civil is not recommended with Revit. It simply isn't equipped to handle things "directly", making people use pseudo methods to get something to work.

    I do believe there is a decent package out there.

    Here:
    http://www.eaglepoint.com/siteworks-for-revit/

    and here:
    http://usa.autodesk.com/adsk/servlet...12&id=17578651

    Forgive me for not being able to assist in anything topo or site related. I've only done easy things for presentation purposes or out of sheer curiosity. If this is more your line of work and need additional commentary or support, try hoping over to www.RevitForum.org for a slew of Revit guru's that may shed more light on topo/site related modeling in Revit.

    -TZ
    Tannar Z. Frampton ™ | Frampton & Associates, Inc.

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