Face Centroid and Area Properties
Get accurate face properties: Centroid, Area, Moment of Inertia and Radius of Gyration
Face Centroid and Area Properties

This plugin will calculate accurate area properties for planar shapes (centroid, area, perimeter, Moment of Inertia, Radius of Gyration). These shapes must be drawn parallel to the X-Y plane (the ground plane) in SketchUp. Of course these shapes must be closed so that a single face is generated by SketchUp.

Usage:

To calculate area properties, select one or more faces and choose “Get Face Properties” from the right-click context menu. The plugin will then calculate area properties for each face successively. These will then be displayed in a dialog that allows for copying of values. As final step, a construction point and a set of X-Y axes can be drawn at the area centroid.

To be able to accurately calculate faces that contain internal holes, you must draw lines for each internal hole that connect the hole to the face perimeter (as shown in the image above).

There are other plugins available that use a similar concept and draw a centerpoint. This is usually done for the center of the bounding box, which only in the case of a rectangle coincides with the area centroid. Please note also that the accuracy of the calculations is dependent on the accuracy of the polygonal shape. While SketchUp draws lines accurately, curves are always approximated by a polyline.

More Info and Help:

http://www.alexschreyer.net/projects/centroid-and-area-properties-plugin-for-sketchup/

Reviews

Does this work on sketchup 2017? i do not see the option to choose “Get Face Properties” from the right-click context menu.

alexschreyer's picture

It should. Make sure you select an ungrouped face before you right-click on it. The context menu option makes sure you have something selected that it can work with.

Does this work on sketchup 2017? i do not see the option to choose “Get Face Properties” from the right-click context menu.

Chip F's picture

Hey Alex, Thanks a lot. I'm working from your "Architectual Design for SketchUp", and am almost done gathering the plugins you recomend. It's going to take a while to learn all of this stuff. I would really be at a loss without your excellent book, I find it is indispensable in putting all this together. Do you have any more books in the pipeline? This extension works perfectly, right from the initial use. Your guidance is really appreciated.

Davesh S.'s picture

installed in 2014 , cant see the plugin . how to use ??

John D's picture

When i right click a selected face i do not see 'Get Face Properties' on the right click dialog menu thata appears !

OK I see my mistake now. Your plugin only works on the ground plane ! While i am ignorant of the effort required to make this plugin it really is lacking functionallity without the ability to find the centroid of any face on any plane !

In its current form it is not efficiant with too much extra operations required to be done making it inefficiant in a fast work flow.

alexschreyer's picture

You are completely right - at some point I should implement this functionality. For now you can use my Flatten Faces plugin to flatten a face and then this one to get its properties.

Olive P's picture

Hi Alex
please can you advise me
i am looking to calculate fabric usage on a whole structure
would you use this add on of yours
thanks
Olive

Steffen K.'s picture

It's already a very useful tool, thanks a lot.
It would be mindblowing if you can provide the neutral axis as well and then it shouldn't be so far to the section modulus.
Maybe we can colaborate for that matter!?

alexschreyer's picture

I have to look back at the code but I think I can provide the strong axis angle. Feel free to look at the Github repository and suggest edits.

Ryan B's picture

I installed this. Where do I find the tool? Sketchup 15

alexschreyer's picture

Select one or more faces and choose “Get Face Properties” from the right-click context menu.

Hamza A.'s picture

Very useful for so many applications. Thanks!

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Face Centroid and Area Properties (1.3); March 5, 2014
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I am a Senior Lecturer at the University of Massachusetts and author of the book "Architectural Design with SketchUp". My favorite topics are SketchUp, AEC-CAD/BIM, Wood Engineering, Web Design, and Photography.