How to Read the Evaluation of Expression Properties in Archicad

When seeing the evaluate output for property expressions you might think: “What am I even looking at?”. The wall of text presented is not very easy to decipher at first. After reading the post you will have a clearer understanding of what information is presented to you.

Colored Example

For the following example, I selected a roof element and clicked the “Evaluate…” button in the Property Manager. To learn how to interpret the output of the evaluation, we will read the evaluation on the right of the following picture from top to bottom.

First we see which Property is evaluated and to which Property Group it belongs.

Next we see the number of selected elements. In this case it’s only one. And below that, the Element ID of this selected element is displayed.

Now we start evaluating the expressions as defined in the sequence of the property. The first expression “Surface Area of the Slab Top (Conditional)” cannot be evaluated since we have a roof selected and not a slab. If an expression cannot be evaluated the result is displayed as three dashes - - - together with a descriptive note.

Then we see the second expression “Surface Area of the Roof Top (Conditional)”. This second expression CAN be evaluated for the selected element and its value is 404.75 m². Archicad doesn’t even try to evaluate the third expression since it already successfully evaluated one expression! And this result is repeated as the final Value of the Property.

Try it Yourself

Now try your new skill in practice!

  1. Open your latest Archicad Project
  2. Select an element
  3. Open to the Property Manager
  4. Select an expression property (You can type “Expression” in the search bar to find one quickly)
  5. Click the “Evaluate…” button


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