centroid

Replies to This Discussion

Permalink Reply by Daniel Piker on March 26, 2010 at 3:00am

You can use Brep area (Surface>Analysis>m²) - which has a centroid output, if you make it a Planar surface ( Surface>Freeform>Planar Srf) first.

Permalink Reply by Miguel Vidal on March 26, 2010 at 3:05am

Thanks, Daniel.

Permalink Reply by P. Casey Mahon on March 26, 2010 at 7:18am

You can also use the Brep Volume (Surface>Analysis>m3) for the center of a volume...try a boolean union of all the solids and the volume of that should give you a centroid for the whole form...probably not exactly where the center of gravity would be though

Permalink Reply by Vicente Soler on March 26, 2010 at 10:10am

The fastest way (computing wise) is just add together the vertices of the polygon and divide the result by the number of vertices.
This solves faster than the m2 and m3 components, maybe it's because these also compute area calculations or/and maybe it's because it doesn't special case polygons and uses a slower method that solves any type of nurb surface.

Permalink Reply by Danny Boyes on March 26, 2010 at 11:30am

Hi Vicente,

I was curious and tried your vertices addition to see what the outcome would be relative to computational speed. But the results were different. I tried it two ways vector addition/divide (magenta) and point decomposition etc (blue) see picture. Have I made a mistake or is there a wheel off here? My Brep is only created from boxes in the regular world axis, there's no bulges in the faces etc.

Permalink Reply by Vicente Soler on March 26, 2010 at 12:41pm

The adding vertices only works for regular polygons and triangles, sorry. But also serves as a quick approximation for more complex ones. To find the centroid of breps and more complex polygons you have to use other methods.

Permalink Reply by taz on March 26, 2010 at 3:25pm

Another option for non-planar curves:

Permalink Reply by phillip on July 14, 2011 at 7:10am

Hi I am currently working a lot with center-points of srfs. Anyone found out a way to just get the centroid without calculating the areas/volumes so far?

Permalink Reply by Juan Pablo Costa on June 8, 2016 at 8:19am

super effective. thanks!