Wish List System
2012-11-26, 08:59 AM
Summary: In previous versions, we were able to specify a negative material density. This option has been removed in IV 2013, making our models unusable.
Description: In previous versions we used a part with negative density similar to seawater to calculate submerged weight and CoG.
In IV 2013, it seems that the ability to calculate negative mass is not longer available.
This is how it worked in pre 2013 IV, when I could specify a negative density.
What I have is a spool made of steel. This spool is modelled as an iAssembly with four configurations:
-In air, empty
-In air, filled with glycol
-Submerged, empty
-Submerged, filled with Glycol
For this example, I now need three parts:
-Steel Pipe
-Glycol derived from the inside volume the pipe
-Seawater buoyancy derived from the outside volume of the pipe.
Each part has its own density, and the assembly weight and CoG correspond to the assembly configuration (with or without glycol) and environment (in air or submerged).
The seawater buoyancy represents the water displaced by the total spool assembly, regardless of the contents. To achieve correct weight in the submerged state, the buoyancy material has to have a negative density.
Product and Feature: Inventor - Part Modeling
Submitted By: Thomas Hauglien on 11/26/2012
Description: In previous versions we used a part with negative density similar to seawater to calculate submerged weight and CoG.
In IV 2013, it seems that the ability to calculate negative mass is not longer available.
This is how it worked in pre 2013 IV, when I could specify a negative density.
What I have is a spool made of steel. This spool is modelled as an iAssembly with four configurations:
-In air, empty
-In air, filled with glycol
-Submerged, empty
-Submerged, filled with Glycol
For this example, I now need three parts:
-Steel Pipe
-Glycol derived from the inside volume the pipe
-Seawater buoyancy derived from the outside volume of the pipe.
Each part has its own density, and the assembly weight and CoG correspond to the assembly configuration (with or without glycol) and environment (in air or submerged).
The seawater buoyancy represents the water displaced by the total spool assembly, regardless of the contents. To achieve correct weight in the submerged state, the buoyancy material has to have a negative density.
Product and Feature: Inventor - Part Modeling
Submitted By: Thomas Hauglien on 11/26/2012