Orca3D News

Tuesday, February 7, 2012

Setting the Fluid Density in Orca3D

When computing hydrostatics, it's important to be aware of the density of the water that the vessel will be floating in. Is it seawater, freshwater, or something in between? What is the water temperature? There are a number of "standard" values for the density, so if your customer (e.g., a classification society) has specified a value, you should use that in your analyses in Orca3D.

Orca3D allows you to specify the fluid type and corresponding mass density. The default is seawater, with a mass density of 1025.9 kg/m^3. To change this, select Properties in the Orca3D menu. In the Properties dialog, click on the Hydrostatics tab. There you can select a Fluid Type of Seawater (1025.9 kg/m^3), Freshwater (999.0 kg/m^3), or Other (which allows you to enter the Mass Density).

If you routinely use something other than the default Mass Density, and/or other custom Orca3D and Rhino settings, an easy way to start each new design is to set all of the settings (fluid density, Orca viewports, Orca units, Rhino units, grid settings, etc.), and then save the file as a template (File/Save As Template). When you start Rhino, type New, and select your template from the list. If you want to automatically use this template each time Rhino starts, check the box next to "Use this file when Rhino starts."