Closed Geometry

smak · December 27, 2015, 12:18

I wanted to ask that what is exactly meant by closed volume or closed geometry? Say in a cad, there shouldn't be an empty space inside?

agd · December 27, 2015, 13:01

A better term is watertight. If you placed the geometry in a bucket of water would the interior remain dry or would you have a leak. A closed geometry is one that is watertight.

smak · December 28, 2015, 02:29

So all the extrusions and the lofts that are solid should be closed whereas the surfaces that are not convex would be open(or not closed) geometry, right!

I do not understand the concept why air interactions in softwares like Altair Virtual Wind Tunnel need a closed geometry. They should even be able to simulate the vortices or so in the real car right if it has a not-closed geometry!

agd · December 28, 2015, 11:04

Closed geometry is more of a requirement for the mesh generation. You only want mesh where you actually have flow, and unnatural surface concavities (such as between surface patches that don't match up perfectly) tend to break most meshers.

December 27, 2015, 12:18	Closed Geometry	#1
smak New Member Sagar Join Date: Dec 2015 Posts: 4 Rep Power: 10	I wanted to ask that what is exactly meant by closed volume or closed geometry? Say in a cad, there shouldn't be an empty space inside?

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December 27, 2015, 13:01		#2
agd Senior Member Join Date: Jul 2009 Posts: 357 Rep Power: 19	A better term is watertight. If you placed the geometry in a bucket of water would the interior remain dry or would you have a leak. A closed geometry is one that is watertight.

December 28, 2015, 02:29		#3
smak New Member Sagar Join Date: Dec 2015 Posts: 4 Rep Power: 10	So all the extrusions and the lofts that are solid should be closed whereas the surfaces that are not convex would be open(or not closed) geometry, right! I do not understand the concept why air interactions in softwares like Altair Virtual Wind Tunnel need a closed geometry. They should even be able to simulate the vortices or so in the real car right if it has a not-closed geometry!

December 28, 2015, 11:04		#4
agd Senior Member Join Date: Jul 2009 Posts: 357 Rep Power: 19	Closed geometry is more of a requirement for the mesh generation. You only want mesh where you actually have flow, and unnatural surface concavities (such as between surface patches that don't match up perfectly) tend to break most meshers.