Monday

Inventor Inspect Tab – Region Properties

Do you remember the equation for Area of Circle, how to calculate the Perimeter of a Circle  . . .

The answer would be just yes but when asked to calculate using equations, then there is a silent.

Don’t worry, Autodesk Inventor does all this for you including finding these

• Area
• Perimeter
• Inertia Tensor
• Polar Moment of Inertia
• Area Moments of Inertia with respect to Principal Axes
• Radii of Gyration with respect to Principal Axes

Let’s go back to basics:

Let see how we can find these for a circle of diameter 50mm

Calculating Area of Circle :

1. Figure out the length of the radius. This may be as simple as dividing the diameter by 2.
2. Note the formula. The formula for finding the area of a circle is:
   
3. Multiply the radius by itself to square it.
4. Multiply by pi.
   • If the instructions say “leave in terms of pi”, then just stick the pi onto your number.
   • If the instructions say anything about rounding, replace pi with 3.14 or use your calculator’s pi button.

For a Diameter of 50mm the area of circle is ~ Area = 1964.28 mm^2

Calculating Perimeter of Circle:

Perimeter of a Circle

1. Start by finding the diameter of the circle. The diameter of a circle is the longest straight line that you can measure along a circle from one point to another. Once you have determined the length of the diameter of the circle you will be better able to determine what the circumference or perimeter of the circle is.

2. Use the diameter of the circle that you have acquired to aid you in the determination of the perimeter of the circle. You will take the diameter of the circle that you have and you will then multiply it by the value pi. The value of pi is a given at 3.14 in most cases and in its simplest form, if you would like to be more accurate you can carry it out to more decimal places if you like.

3. Apply the information to determine the circumference or diameter through examples. If the diameter of the circle is 15 and then you multiply that by pi or 3.14 you will get a distance of 47.1 units as a perimeter. Make sure that you use the proper units when you state the answer that you get for the problem.

4. Determine if the length that you have in your problem is a radius or a diameter. If it is a radii it will need doubled or multiply it by 2 in order to get the right answer for your problem about the perimeter of the circle.

For a Diameter of 50mm the perimeter is ~ 157.14mm

If I further move deep in calculation; as I know some of you may just leave the room or some may just start talking negative against me. So what’s the solution ?

We can calculate all these using Autodesk Inventor 2010 Region Properties using the Inspect Tab

Let’s begin the tutorial: Create a sketch (circle of diameter 50mm), now in order to calculate the all the above properties its simple, just click on the Inspect Tab and select Region Properties as shown below

Region Properties

Now go ahead and select the sketch loop for which you need to calculate the area, perimeter, and the Area Moment of Inertia properties.

Note: All measurements are taken from the sketch coordinate system.

Calculation:

Calculation occurs automatically when the selection is made. In addition, this command recalculates results after adding to the selection set.

• Area and Perimeter provides cumulative area and perimeter values if multiple sketch loops are selected.
• Centroid Location displays the X and Y distances from Sketch origin to Centroid.
• Inertial with respect to Sketch Origin provides Inertia Tensor and Polar Moment with respect to the sketch origin.
• Area Moments of Inertia with respect to Principal Axes provides Principal Moments, Polar Moment, Rotation about Z Axis, and Radii of Gyration, with respect to the Principal Axes.

For a circle of diameter of 50mm these are the results displayed

Region Properties Results

I hope these tools will be of great help to you, increasing your productivity to a greater extent.

We can go ahead a find all the above parameters for a complicated closed profile too.