Category Archives: ARCHICAD Training

It takes two floors to make a story, but only one sacrificial story to stuff it all up

Further to my previous post “How to prevent your ARCHICAD model from becoming detached from Sea Level” I was asked to follow it up with an example.

For the example, I decided to use the project file supplied by GRAPHISOFT, Volume 5 – Using Teamwork. The building used is the Microsoft Office Complex in GRAPHISOFT Park, Budapest, Hungary. That way any reader of this article can download the file for reference purposes if they so wish.

Example 1
Let’s first look at the correct way with the use of Project Zero using Story 0 = Ground Floor slab (street level). It uses a logical story relationship of Story -1 = Basement, Story 1 = First Floor, Story 2 = Second Floor, etc.

Project Zero Image 1

Looking at any of the sections or elevations one can see the “0 Ground Floor = 0.00 setup using Project Zero / Reference Level.

Project Zero Image 2

The next step is to insert a Sea Level reference. The default settings for Project Location are indicative that it has not been setup to match Google Maps. For now, I am just going to insert the value of 10 m for “Altitude (Sea Level):

Project Zero Image 3

Then looking at any of the Elevations or Sections to see the Sea Level relationship, if one selects all four sections in the Project Map and right-click (context menu) the option “Section Settings…” then under the drop-down menu STORY LEVELS > Reference Level change the option to Sea Level.

Project Zero Image 4Project Zero Image 5

Now when opening any of the Sections one will see the logical story relationship of -1 Basement +6.40, 0 Ground Floor +10.00, 1 First Floor +13.60 etc to Sea Level.

Project Zero Image 6.png

When opening the layout A-06 Section one will see that the four sections will update to show the 10m to Sea Level reference. But please note the section to layout placement is not affected by the addition of 10m.

A-06 Sections _ Layout

Therefore making use of the Relative Level – Project Zero = Ground Floor and changing the Sea Level value will not have a knock-on effect of the building model moving up or down, including layouts becoming disassociated. In other words, Sea Level moves up or down not Project Zero.

Example 2 (Not recommended)
Using a sacrificial story named Datum / AHD to “push-up” the building model to sea level. To achieve this, I opened Story Settings and inserted two stories above 0 story by selecting it and clicking “Insert Above” twice. Then I used the “Edit Element by Stories” found under the Design menu to cut & paste from Story 0 to Story 2 and Story -1 to Story 1. Then I typed in the letters Datum/ AHD into the name field for Story 0 and renamed Story 1 Basement and Story 2 Ground Floor.

Project Zero Image 7Project Zero Image 8

Please note: that elevations and sections have moved in relationship to the 2D drafting work that was placed on them to clean them up. Including “Elevation levels” have become disassociated. For the screenshot example below I used trace & reference to illustrate the issue of using 0 Story as a Datum / AHD.

Project Zero Image 9.png

Last but not least making any adjustment to the use of Story 0 as Datum / AHD is going to affect the entire building model and document set. Working for a large Architectural Practice like Plus Architecture, I can tell you that disassociated document sets are not appreciated by anyone.

A-06 Sections _ Layout_disassociated

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How to prevent your ARCHICAD model from becoming detached from Sea Level.

The relevance of Project Zero, Sea Level / Altitude / AHD, Reference Levels & Home Story Settings

Looking at how to get a building to relate to sea level in ARCHICAD is an interesting topic for discussion and in my opinion has been prone to interpretation. I have had many a debate with other ARCHICAD users over these past few years regarding the “correct” way to use it. My take on the subject is that I use it the way GRAPHISOFT intended it to be used. A big game changer was one of the new features of ARCHICAD 16.

Better Project Location/Project North Definition > Define a Project Altitude relative to Project North; optionally use the Altitude value as a fixed Reference Level in Project Preferences, available in all dialogues that refer to a Reference Level

The relevance of this is that the field “Altitude” found in Project Preferences > Project Location sets the “Elevation” field for “Sea Level” found in Project Preferences > Reference Levels. In other words, they are directly correlated.

Project Location to Project Preferences.png

The most important part to note is that the actual elevation values of any model elements are always calculated from Project Zero and that reference levels are for display and input aids. Another way to put it is Project Zero never moves up or down; it is a fixed reference point. Changing the value Altitude (Sea Level) does not affect Project Zero. In other words, the building related to Project Zero does not move, but Sea Level does.

project zero & sea level

Let us look at the term or definition of “Project Zero” before continuing.
When teaching ARCHICAD to new users, I like to explain that Project Zero = Reduced Level in surveying terms.

In other words, Project Zero is the adopted datum plane for the start of the building model; it is horizontal and commonly assigned to the top elevation of the Ground Floor slab, placed on Story No. 0 – Ground Floor (street level).project zero - GF

For those American readers of this blog, I would like to point out that the localized version of ARCHICAD USA; Story settings start with story No. 1 – 1st Floor. It is of course due to the difference in British and American English: the naming of floors in buildings.

In British English, the floor of a building at street level is called the ground floor. The floor above it is the first floor, and the floor below is known as the basement.

In American English, however, the floor at street level is usually called the first floor. Go up one floor and you are on the second floor (which, of course, is the first floor for the British). The floor below street level is called the basement, the same as in British English.

In other words for America, Project Zero is assigned to story No. 1 – 1st Floor (street level).

ARCHICAD USA Story Settings

Just to reiterate the use of “Altitude” has been with us since it was introduced in ARCHICAD 16. Which was announced on May 2, 2012, more than 4 years ago

A functionality improvement for ARCHICAD 19, was the inclusion of “Altitude (Sea Level).” My thanks go out to James Badcock, who is a Product Designer at GRAPHISOFT HQ, who advised me that he was responsible for putting in the request to the Product Team to insert the words “Sea Level” after Altitude.

Altitude (Sea Level)

Reference Levels Preferences

Note: You cannot rename the Project Zero or Altitude reference levels.
Note: Reference Levels are display and input aids only. Changing their value has no effect on placed elements, whose actual elevation is always calculated from Project Zero. The exception is Grid lines in Section view, whose position changes with the Reference Level.

But you can rename the 2 provided Reference Levels and change their Elevation value. This is especially useful when working on a building that has split levels.

Project preferences 1st Ref

Reference levels can also be used as reference levels for showing elevation (Z) values in the Tracker. When entering a distance using Tracker, keep pushing Tab to get to Z Coordinate and click on the small arrow to show “Elevation Value Origin”.

Elevation_Value_Origin.png

 

What does this mean for the user, and how did GRAPHISOFT envisage that it should be used? The answer lies in the simple fact that when looking at Story Settings, there is no need to insert any value into Story Settings to get the model to relate to Sea Level.

Looking at it from an Australian perspective and the use of AHD or Australian Height Datum. According to:

Wikipedia – Australian Height Datum

The Australian Height Datum is a geodetic datum for altitude measurement in Australia. According to Geoscience Australia, “In 1971 the mean sea level for 1966-1968 was assigned the value of 0.000m on the Australian Height Datum at thirty tide gauges around the coast of the Australian continent. The resulting datum surface, with minor modifications in two metropolitan areas, has been termed the Australian Height Datum (AHD) and was adopted by the National Mapping Council as the datum to which all vertical control for mapping (and other surveying functions) is to be referred.

It is my opinion that “Australian Height Datum” or AHD for short is just another way to say “sea level”. And that in ARCHICAD, the use of the value field for “Altitude (Sea Level) is the same as AHD as it was assigned the value of 0.000m.

The use of “Story Settings” in ARCHICAD INT is to represent the logical story structure of the building starting with:

  • Story 2 = Second Floor
  • 1 = First Floor,Story 0 = Ground Floor = Project ZeroStory  Story 2 = Second Floor etc. Therefore when looking at Story Level Lines, they follow the same logical progression. Inserting a story below Story 0, results in Story -1 which can be used for Basement / footings / foundation.

Story 1 = First Floor, Story 2 = Second Floor etc. Therefore when looking at Story Level Lines, they follow the same logical progression. Inserting a story below Story 0, results in Story -1 which can be used for Basement / footings / foundation.

-1 Basement story setting.png

Looking back, to before “Altitude” was introduced in ARCHICAD 16, namely versions 15, 14, 13, etc. there was still one of the two Reference levels (1st or 2nd) that could be substituted and renamed to AHD or Sea Level.

AC15 Levels & Project North.png