Volume Calculation


Ken Willingham
How is the volume calculated in Segment Pro? Is it by external or internal row measurements? (I suspect internal after turning smooth.)

I'm designing a pair of cremation urns for me. This is an important calculation for reasonable accuracy.
I'll get divided into 2 urns for offspring that get an urn to dump into the ocean on their side of the country.
Thanks for any guidance on this project.


Super Moderator
Staff member
Found this in another thread that Lloyd posted. I like the tip of 1 pound = 1 cubic inch for ashes.

"I start with row #2 and stop at 1” from the top of the turning to accommodate for the lid. While this may not always be correct for the design you are making, it should be close enough because the calculation of 1 pound = 1 cubic inch is a rule of thumb that is not based on science.

Seems this is the formula used in the sotfware.
V = pi x h x (R2 + r2 + R x r) / 3 where h=height of vessel, R = major radius and r = minor radius.

Lloyd Johnson

Staff member
Yes, that is the formula I use. I use the inside diameter from each of the two adjacent rows along with the height of the lower row and then add them all together to get the total volume.

I have used online calculators to verify my calculations but, and this is important, I make NO guarantee as to the accuracy of my volume calculation. The formula is correct and the methodology seems legitimate but my intention is to provide a thumbnail view estimate only.

As Mike also showed, the calculation of one live pound to one cubic inch of volume has no basis in science and varies from person to person so at best, this can only be considered a rough estimate.

I recommend substituting the same volume of rice to the physical volume of ashes and build a bowl from mdf to verify results.



Ken Willingham
I believe the formula and description to be accurate enough for my needs. I've read in several places that the 1 pound of body weight = 1 cu. inch of urn volume is the closest I can hope for so I'll use that.
Thanks, Ken
These 2 urns are for me to go to my 2 children, One on each coast with 1/2 of me in each one. I always liked the ocean waves and would like to be spread there. ;)