How to calculate and display the mass properties (volume, surface area, and centroid) of a model.
The tool provides two ways of specifying the object to measure:
- – The surfaces you pick represent the boundaries of a closed, solid object.
- – The surfaces you pick represent the outside of a thin shell enclosing a hollow space (for example, modeling a bottle with
a single surface of revolution). You specify the thickness of the shell.
Restrictions
To get accurate statistics on an object, the following conditions must be met:
- The surfaces must completely enclose a volume. The edges of surfaces must meet within the tolerance value set in the option window.
- The normals on all NURBS surfaces must point out of the solid, and, when moving along a face boundary in the increasing U
direction, the face area must be to the left when viewed from outside the solid.
or
The normals on all NURBS surfaces must point into the solid, and, when moving along a face boundary in the increasing U direction,
the face area must be to the right when viewed from outside the solid.
You can check the seam between two surfaces by placing a measurement on the seam. You can check the orientation of normals using thetool.
Show the mass properties of a model
- Pick all the surfaces that make up the model. Make sure the surfaces completely enclose the volume of the object.
- Click the icon, or choose Evaluate > Mass Properties from the palette.
When the tool completes its calculations, the window appears, containing the following statistics about the object.
Label |
Description |
Formula |
|
Current unit of measurement (default is either centimeters or millimeters, depending on which product you are using). |
|
|
Area of the picked surfaces. |
|
|
Volume enclosed by the picked surfaces, or volume occupied by shell surface with given thickness. |
|
|
X, Y, Z coordinates of the center of the object |
|
Note
If you are using a construction plane when you click the tool, the calculations use the X, Y, and Z axes of the current construction
plane.
If you change the options of the tool, the window updates.