# Thread: Centre Of Buoyancy calculation

1. Hi all Pro-E users,
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2. Just create a Shrinkwrap of the Assembly and merge the entire assembly into a single solid part, if its comepletly submerged, center of mass of that single solid part (shrinkwrap) is the center of boyancy. if only part of it is submerged, make a datum plane at water level,solidify(cut) the portion above that plane and then calculate the center of mass which will be the center of buoyancy.
Edit: if you have enclosures inside your assembly then you have to fill them before you can calculate center of buoyancy.you get the correct results only if you solidify the volume of displaced water.

Edited by: solidworm

3. Thank you for the reply solidworm.
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Did this method work for you?

I have tried a similar method in Pro-E.
1. I make a

4. how does one calculate the the water level though?

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5. An important note to consider!
you get the correct results only if you solidify the volume of displaced water.

Shrinkwrap is a better option in my opinion because it remains associative with your assembly and you don't have to change densities.it creates a single part out of your assembly with a constant density throughout and filling the required spaces if necessary is easier in part mode. (open a new part>insert>shared data>shrinkwrap> select "autocollect all solid surfaces" and the option to create a solid.) again, you have to make sure the resulting geometry is exactly the displaced volume, modify and fill the required volumes if necessary (for example for enclosures and the cases like a floating bowl)

Edited by: solidworm

6. I will try the shrinkwrap way. Hope it works.

7. This is what you should be careful about. Here's a section view of a cylinder assembly with a different material for each part,suppose its completely submerged in water, creating a shrinkwrap, converts it into a single solid part. but you need to remove the enclosed space to get correct results. (using edit>remove) only in this case COG of shrinkwrap is the center of buoyancy.

Assembly:

Shrinkwrap with enclosed space removed (edit>remove):

Edited by: solidworm

8. Is the edit>remove function part of advanced assembly? I can't seem to find this command in the menu? I'm using Creo 3.0.

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