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ArchiCAD Tip - Polygon Counting Add-on


In certain ArchiCAD models, the number of polygons/surfaces required to generate the 3D model can grow to a very large number, and as a result, the time taken to generate 3D views can increase dramatically.

Elements that can increase the polygon count include:

As well as the 3D window view, Section and Elevation views are also derived from the 3D Window, even though they are 'flat' 2D views, and when shadow casting is turned on in Sections/Elevations, the regeneration time for these views can really increase.

If a situation occurs when the view generation time seems to be too long, it may be useful to analyse your ArchiCAD model to see what elements are contributing a large amount of polygons.

The 'PolyCount' Add-on allows you to analyse the 3D model giving a breakdown of where complexity is in a model - It is a free add-on found on the Graphisoft website.

NOTE: You must download and install the correct add-on version to match your ArchiCAD version.

  1. Save the file to your desktop
  2. When fully downloaded, double-click the file to start installation
  3. Choose all the default options to complete the installation
  4. Note the option on the final screen to access the latest Hotfix
  5. When installed the downloaded files can be deleted

The reasoning for this is given on the 'Add-Ons' webpage – the simple explanation is that you must run the latest Hotfix whenever you add a Goodie Add-on to allow the Add-on to be updated to the most current version (i.e. the online add-ons are not the most up-to-date)

Using the Add-On
When installed, re-open any ArchiCAD instances, open a project, and go to the 3D window.
Go to the "Window > Palettes > PolyCount" pulldown menu and click 'Refresh' on the dialog. (Note the (expandable) Element/Polygon breakdown.)

This breakdown display a list of polygons per element and also a percentage of the overall 3D polygon per element - this is where any inappropriately large elements can be identified and either removed or replaced.

Another tip for using this tool is that the PolyCount will only analyse elements shown in the 3D window, so if you only show a certain set of elements (as opposed to the full model) you can analyse elements more finely.
This is very useful when two instances of the same object are placed in a scene but one may have a higher level of detail - you can compare each instance individually.

For example, a complex chair/tree object placed numerous times in a scene, may generate over 60% of all polygons in that scene, whereas if replaced with a less-complex (but still appropriate) chair/tree object, it may reduce to 3% of the overall polygon count.

In a model that inadvertently has a large polygon count, analysing and reducing the number of polygons can be extremely useful as it can:

A very simple ArchiCAD model can be found here, with a number of elements placed - it is a perfect example of how similar objects can yield far different polygon counts (between 6x and 10x in this example).
(Hint - Both trees are the same object but with different 3D complexity, set in the object's parameters)