Week #12 – Site Survey and Topography Modeling
12-1. Introduction to Site Modeling: DWG Import and Working with the Mesh Tool

ArchiCAD Training (Best Practices Lesson 12-1)

This 49 minute introduction to site modeling is borrowed from the QuickStart Course (Module 7 Part 2). It covers the import of a DWG file to proper scale, which is placed into an independent worksheet and used as a Trace Reference for building a terrain model using the Mesh tool. A previously-modeled building is coordinated with the sea level datum reference. Some site improvements are added, including both hardscape and landscape elements.

Two versions of the DWG are available here on this page for following along with the video, one in imperial (feet) and the other in metric. An independent Worksheet is created for placing the DWG into the file; in versions of ArchiCAD that do not have worksheets, an independent Detail window may be used, or in version 10, an extra “dummy” story may be created so that the “ghost story” option provides a tracing image similar to Virtual Trace.

Ideally, the scale of the Worksheet (etc.) should be set to the intended printing scale (e.g. 1/8″ = 1′-0″ or 1″=20′-0″ or 1:100 etc.) of the site plan before importing the DWG so that the text appears correctly in relation to the site geometry. The File menu > External Content > Place External Drawing command is used to import the DWG. (In the Start Edition one may use the File menu > File Special > Merge command instead; the effect is different, but for this lesson it will work just fine.)

While placing the DWG, the Drawing Unit dialog offers the opportunity to confirm the size of the internal DWG measurement unit, which will generally be Feet in the U.S. and may be Meters or Millimeters in international usage.

After importing the survey, it is important to verify that a known distance from the drawing matches the distance displayed by the Measure Tool. If it does not, then the simplest way to correct this is to calculate the proportion difference (e.g. the size is 12 times or 10 times too big or too small, etc.) then Undo, and reimport using a different measurement unit. Repeat if necessary until the survey dimensions are verified as accurate.

On the ground floor, a new View is created with the Site layer combination. (Note that the Quick Options palette makes it easy to change layer combinations on the fly.) If necessary (as demonstrated in the international project file) it may be useful to adjust the Site layer combination to include the exterior walls of the building; remember to Update the layer combination after making the change so it is recorded properly.

The survey worksheet is set up as a Trace Reference, then with the Drag Reference command (using the button in the second row, second from the left, in the Trace and Reference palette) the survey image is repositioned to coordinate properly with the building.

The relationship of the current Project Zero – often this is set as the top of the finish floor of the main story – to Sea Level or a standard height datum – is set in the Options menu > Project Preferences > Levels and Project North (or a similar command; this varies in different versions of ArchiCAD). The Sea Level or Reference Level is set to the appropriate offset from the Project Zero so that when the terrain is created it is easy to input and reference grading elevations based on the external datum value.

The Mesh Settings elevation is then set up to reference the Sea Level or Height Datum rather than the Current Story or Project Zero. An initial base is created by tracing the outline of the site boundary, snapping carefully to each node point. After the mesh is in place, it is viewed in 3D – it is a flat slab, floating a bit below the building.

To edit the details of the mesh height values, it is important that the mesh tool be active in the Toolbox, and the mesh be selected. Each node point is clicked on, and using the pet palette Z-height option, set to the appropriate height above Sea Level or the Height Datum. Do not click the Apply to All checkbox when changing the Z-height; do each one of these nodes one by one. The mesh is viewed in 3D again, and now the prevailing grade is clearly visible, and the building is partially enveloped by the terrain.

Before creating each topographic contour,  add new node points where that contour line meets the site boundary, then set the height of each node properly. This sets the exterior of the mesh to a more precise representation of the grade.

To create a contour line, click slightly inside the mesh perimeter, then click a series of points to roughly trace the topographic line. Click twice on the last point to finish, and accept the default choice (“match to existing contours) in the Add Points confirmation dialog box. After creating the contour line, with the mesh still selected, press down on any of the interior points of that polyline, and use the Z-height option in the pet palette to set the height of all of the points in that polyline (click the checkbox “Apply to All”).

Repeat the process for additional contour lines as needed, and know that you can add more at any time. Do not overdo it, and don’t put too many node points while tracing – this will add needless polygons (detail) to your model that may slow down the responsiveness as you view and work in 3D.

The mesh element may be set to display all contour lines on the plan, which can get messy as more contours are drawn and ArchiCAD calculates all the triangular surfaces necessary to represent the geometry. To turn this off, use the option in the Floor Plan and Section panel or popup > Outlines to Show User Defined Ridges rather than Show All Ridges. A similar option exists for the 3D model representation, which you may adjust in the Info Box or the Mesh Settings: choose All Ridges Smooth in the Model panel.

  • NOTE: In the QuickStart Course, a building has already been modeled by the student and can be used as part of the lesson. For Best Practices Course members, I suggest that you quickly create a simple rectangular slab and four walls, and use these as the model building in this exercise.

When viewing the Sections of the building, use the Design menu > [Connect submenu – in ArchiCAD 15] > Solid Element Operations (SEO) command to carve out the floors from the terrain mesh. Select the floor slab and make it the Operator, select the terrain mesh as the Target, and use the Subtraction with Upward Extrusion command – voilà – the terrain is cut to make way for the floor and walls above.

To add hardscape such as a patio, use the slab tool and set the elevation properly, perhaps by eye-dropping an actual floor slab. If it is buried in the terrain, use the SEO palette to carve out the slab from the terrain. This may be done from the plan view, since it is easy to select each of the elements.

The slab hardscape may be set to a different material, perhaps a concrete or stonework. If you’d like to see a hatch pattern on the plan, you may activate the Floor Plan and Section > Cover Fill option, and either use the Fill that is associated with the material, or set it to an independently selected Fill.

Finally, the object tool is opened and tree objects are located using the Find by Keyword option. To place the trees at the right elevations in relation to the terrain, the Gravity option is turned on, and the sub-option selected to Gravitate to Mesh (rather than Slab, Roof or Shell). Then when the tree object is placed, either on plan or in 3D, it will pick up the height of the underlying mesh and use that as the base height for placement.

NOTES FOR USERS OUTSIDE THE USA

  • In the final segment of the lesson, the first operations are repeated with the International metric survey to explain a few differences in the setup of the International template and project file. The 01 Site layer combination is enabled, but it does not show the exterior walls; this layer combo is updated to turn on the Structural – Bearing layer, on which the exterior walls are placed. In addition, the mesh tool is set by default to show a Cover Fill; this option is turned off to make it easier to see the working area.
  • If you’d like to see the terrain mesh in your Section drawings, one other change will be necessary in the international version. The clone folder for Sections uses the 04 Plans – Approval layer combination, which does not show the Site & Landscape – Terrain layer. I suggest creating a new layer combination for Sections (in the Layer Settings dialog, activate 04 Plans, and then click the New button in the bottom left to create a new layer combination with identical settings). In that Layer Combination, turn on the Site & Landscape – Terrain layer, and click the Update button to record the change, and click OK. Then highlight the Sections clone folder in the View Map, click on the Settings button, and adjust the Layer Combination to use the one for Sections that you just created.
  • When placing the trees, a good layer combination to use for the international file would be 08 Rendering, since that turns on the Site & Landscape – General layer.

Please post your comments and questions below.

Eric

Thank you for visiting the Best Practices Course website. The video lessons are available for members only. If you are an active member and would like to watch the ArchiCAD training video on this page, please login to the website. If you are not currently a member, please visit the following pages for more information and to sign up for the Best Practices Course, the QuickStart Course or for the Best Practices ArchiCAD Coaching Program. Eric Bobrow, Creator of the Best Practices Course
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ArchiCAD Training: Introduction to Site Modeling: DWG Import and Working with the Mesh Tool

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  1. RandolphMiles
    10 years ago

    Eric,

    I’ve been successfully modeling a terrain based on the principles you outline in this lesson. I watched it three times and have been happily moving along, but I have come to a roadblock that I hope you can easily resolve.

    After creating the mesh and adding the interior user defined ridges, and changing the z-height values using the pet palette, I would now like to move some of the internal node points around to refine the topography. I would think that this would be as simple as selecting an internal node point and choosing the move node option from the pet palette. However, because the previous operation on an internal node had been to change the z-height, it automatically reverts to that option upon clicking a point. If I click Ok (I don’t want to change the z value) the z-height option box and the pet palette disappear. If I click Cancel, the option box and the palette disappear. I can’t seem to change options within the pet palette as it seems to want input from the z-height box to continue.

    How can I change to a different tool within the pet palette after using the change z-height tool?

    Thanks,
    Randolph
    (I’m using Archicad 17)


    • Eric Bobrow
      10 years ago

      Randolph –
      I encountered this problem myself recently, and then heard through a client (who had contacted Graphisoft tech support) that it is a known issue. See the email below for details along with a workaround.
      Eric
      ———————
      Thanks for the email. This is a known bug and there will be a fix for it in the next Hotfix. The issue only applies to points inside the mesh. The workaround is to click on an edge point of the mesh, click “Cancel” on the dialog, then hit Esc. Now click points inside the mesh to edit them with other pet palette commands.

      http://www.archicadwiki.com/Troubleshooting/ElevateMeshPointHeight

      Best regards,

      Nick Cornia
      Technical Support Engineer

      GRAPHISOFT | One Gateway Center, Suite 302, Newton, MA 02458 USA | 1-800-238-3992 | support@graphisoft.com


      • RandolphMiles
        10 years ago

        Eric,

        Thanks. I’ve tried that and it seems to work.

        Randolph


  2. JohnChittenden
    11 years ago

    Eric
    Have done as suggested to the comment below
    I am logged in but can only access an audio file but no video

    Cheers
    John Chittenden


    • Eric Bobrow
      11 years ago

      John and Ahmet –

      I apologize.

      It appears that the permissions settings for the SiteModel Course lessons were set incorrectly, so that the videos for Week 12 (all the lessons on site and terrain) were only visible to full members of the Best Practices Course.

      I have corrected this error, and you should now be able to access the videos for the SiteModel Course.

      Eric


      • AhmetTukel
        11 years ago

        Thanks Eric;
        Just as I was loosing hope that your mail came in this morning and I was able to download the videos of the courses.
        Regards
        Ahmet


  3. AhmetTukei
    11 years ago

    I read the following sentence: ‘Two versions of the DWG are available here on this page for following along with the video’ but cant locate the video! Am I missing something?


    • Eric Bobrow
      11 years ago

      Ahmet –

      Welcome to the SiteModel Course! To see the videos, you will need to login to the site at http://www.acbestpractices.com/login/

      You should then see a video appear (sometimes it takes a few seconds) just above this comments area, at the bottom of the text instructions.

      Eric


    • AhmetTukel
      11 years ago

      Sorry Eric. Nothing appears above the comments area at the bottom of text instructions.
      If you ask, I can send you a picture of what my browser looks like at the end of instructions page but I am sure you’ll believe what I told you.
      So, I have not been able to watch your video tutorials and was left to do with the audio text end the downloaded dwg compressed file which by the way opened perfectly in archicad 15.(I mean imported)
      Have a good weekend


      • Eric Bobrow
        11 years ago

        Ahmet –

        It is possible that your browser settings are restricting the display of the video content. Here are some troubleshooting tips:

        1) Can you see videos on any of the other pages in this module? This will determine if it’s only this page that has a problem, or in general.

        2) Are you seeing a message indicating that the content is private and available for members only? If so, you need to login to the site at http://www.acbestpractices.com/login/ then return to this page.

        3) Try this in another web browser, perhaps Google Chrome or Firefox. Sometimes there can be a problem in one browser (due to settings) and these will not be an issue in another browser.

        4) Try logging in from another computer. See if the problem happens there.

        Let me know what happens. I want you to be able to access the training videos, and there is no reason why you shouldn’t be able to see them – others can see them OK, so should you!

        Eric


        • Eric Bobrow
          11 years ago

          Ahmet – Please see my note to John Chittenden above – this problem was due to an error in our configuration settings. I have corrected it now, and you should have access to these lessons in Week 12, as well as all of Weeks 1 through 5. My sincere apologies for the unnecessary frustrations!
          Eric


  4. RodneyDay
    12 years ago

    Eric,
    Should the dwg file you have above be the same as the document drawing you had in the tutorial, it doesn’t seem to be. It doesn’t have the angles for boundaries etc.
    Rod


    • Eric Bobrow
      12 years ago

      Rod –

      This lesson is about bringing in a very basic DWG with contour lines. There are no angles specified for the boundaries. One just traces them from the DWG.

      Lessons 12-2 through 12-6 show surveys brought in as PDFs; these show complex bearing angles for the boundary lines. In these lessons, the property lines are drafted using the angles specified.

      Eric


      • Eric Bobrow
        12 years ago

        Rod – I have just uploaded the PDF file used in lessons 12-2 through 12-5. You’ll find it just below the lesson video for Week 12 Part 2. I apologize for the oversight of not making it available when I posted the lesson itself. – Eric


  5. RodneyDay
    12 years ago

    Hi Eric,
    I can’t seem to find the pdf that you use in your first site tutorial, could you point me in the right direction.
    Regards
    Rod Day


    • Eric Bobrow
      12 years ago

      Hi Rod –
      In this lesson, I import a DWG rather than a PDF file to use as the basis for creating the site model. You’ll see the download links for the DWG files used in this tutorial directly above the video.
      Eric


  6. AlbertVan Ee
    12 years ago

    Thank you for a very clear instruction as usual. When you bring in a dwg file does it not come in with a set of it’s own layers? How do you deal with them?


    • Eric Bobrow
      12 years ago

      Albert –

      There are many ways to bring in a DWG file. When you do it as a Drawing (placed into a Worksheet, a Layout, or any other window) it is a single element on a single layer. The native, internal layers that are part of the DWG file do not come into the ArchiCAD project.

      Layers in the native DWG are visible or not depending on the state of the layers when the DWG was last saved in AutoCAD.

      In ArchiCAD 14 and 15, Graphisoft extended the controls, so now you can actually turn on or off these “embedded layers” by opening up the Drawing Settings dialog. They still don’t interact with the native ArchiCAD layers, but now you can tweak the visibility of elements in the imported Drawing.

      I’ll be going over this topic in detail later in the course.

      Eric