# Measure Utility

This is a very useful tool which allows the user to examine a selection of geometric values like the surface and volume size for a selected object.

###### The "Measure Utility" icon and its window.

##### Selected node

Here is the object's name displayed whose properties are shown below.

##### Units System

This drop-down menu gives you the opportunity to choose from "Metric", "US" and "Japanese" systems. If you want to get physically correct results from calculations with the given values, please use “Metric”, because this system is used with the SI system, an internationally accepted format of units, for example:

`Mass [ kg ]`

`Velocity [ m / s ]`

`Acceleration [ m / s`

^{2}]`Force [ N ] [ kg · m / s`

^{2}]`Density [ kg / m`

^{3}]

##### Surface

To get the surface size of the current object please have a look at this value.

##### Volume

The volume of an object is of particular interest, because it can be used to calculate whether an object will sink or float:

`Density = Mass / Volume [ kg / m`

^{3} ]

When an object's density is exactly the same as the density of the surrounding fluid, the body will float. If the density is higher, it will sink. Bodies with densities lower than the surrounding fluid will just dip slightly into the fluid and quickly move to the surface. A beach ball is a very nice example for such an object: when you try to push it under water you need a strong force and you can always feel the ball's tendency to emerge.

From a node's volume RealFlow also calculates its mass. The ratio between volume and density is by default always 1.000 kg/m^{3} which is exactly the density of pure water. A “Torus” node, for example, has a volume of 4540.89 l and a mass of 4540.89 kg. To get the volume in cubic metres you have to translate the volume:

`1.00 l H`

_{2}O = 1.00 kg

`1000.00 l H`

_{2}0 = 1000.00 kg

`4540.89 l / 1000.00 kg = 4.54089 m`

^{3}

`4540.89 kg / 4.54089 m`

^{3} = 1.00 kg / m^{3}

##### Vol Bbox

Here you can see the volume of a virtual bounding box that would exactly enclose the selected node.