Computing Weight

You can compute the weight of a part based on its design (3D geometry), its associated material (such as steel or plastic), and its surface material (such as paint or resine). Likewise, you can also compute the weight of an assembly.

Note: If the declared and the computed weight of a part are different, then the declared weight is taken into account.

This task shows you how to:

Compute the Weight of a Part
Compute the Weight of an Assembly
Compute the Wet Weight of an Element

Before you begin: Open the assembly and start weight definition.

Compute the Weight of a Part

You can compute the weight of a part based on its design (3D geometry), its associated material (such as steel or plastic), its surface material (such as paint or resine), and its fluid material (such as oil).

The weight of a given part in an assembly is computed by multiplying the weight of the part (with its material and surface material) by the number of references of the part in the assembly. The error margin defined in the options for computed weight is taken into account in the computation.

In the tree or in the 3D area, select a part for which you want to compute the weight.

Important:

Make sure that the Sheet Metal parts are folded before launching the computation.
You can specify that the computation has to be done on the main body only by selecting the option Force to take into account only main body for weight computation in Me > Preferences.

An information message appears, giving you the choice between declaring or computing the weight of the element.

Click

Click this hyperlink to compute the weight of this element [...].

The weight is computed, based on the design, the associated material, surface material, and the fluid weight. A table appears, displaying the attributes of the selected element:

The weight and error margin,

Note: The error margin computed here is defined in the options. For more information, see Error Margin.
The center of gravity (CoG)
The volume
The moments of inertia (Iox / G)
The products of inertia (Ixy / G)
The mean density
The status of inclusion in weight synthesis
A comment


#	Attribute	Value
1	Weight [Margin]	0.002kg [0.002kg..0.003kg]
2	CoG along X	1.684e-008mm
3	CoG along Y	-2.713e-008mm
4	CoG along Z	-6.478e-009mm
5	Volume	3.176e-007m3
6	Moment Ixx / G	2.036e-007kgxm2
7	Moment Iyy / G	1.093e-007kgxm2
8	Moment Izz / G	1.093e-007kgxm2
9	Product of Inertia Ixx / G	0kgxm2
10	Product of Inertia Ixz / G	0kgxm2
11	Product of Inertia Iyz / G	0kgxm2
12	Mean Density	7860kg_m3
13	Include in Weight Synthesis	Yes
14	Comment

Tip: You can switch from computed to declared weight by clicking Click this hyperlink to replace computed by declared weight in the information message.

Optional: To specify whether the selected part should be taken into account in the weight synthesis of the assembly as a whole, select the Include in Weight Synthesis value cell. Then click the value and either:
- Select Yes if you want the selected part to be taken into account.
- Select No if you want the selected part to be ignored. In this case, the selected part is displayed using the transparent white color.
Optional: Select the Comment cell, then click the value and enter a comment.

The part turns to green, indicating that its weight computation is complete. If there are several instances of the part in the assembly, every instance of the part is also updated with the computed weight and turns to green. The assembly itself is updated to take the part's computed weight into account. The tree is updated, reflecting the computed weight status of the part in the assembly using a green rectangle to the left of the part's name. The percentage of elements with computed weight is updated.

Important: Weight information is not sensitive to design or material modifications. When a physical product has a computed weight and its characteristics (design or material) are modified, it affects the weight information. The characteristics' values need to be updated. An option in the Characteristics preferences forces the Update command to take these modifications into account. For more information, see Customizing Preferences: Characteristics and Assembly Design User's Guide: Update.

Compute the Weight of an Assembly

You can compute the weight of an assembly. The weight is computed based on the weight of the parts, which make up the assembly.

Select the assembly in the tree or in the 3D area.
Click Click this hyperlink to compute the weight of this element [...].
The weight is computed, based on the weight of the parts, which make up the assembly. A table appears, displaying the attributes of the selected element:
- The weight and error margin,
  
  Note: The error margin computed here is the sum of the error margin applied to each part in the assembly. For more information, see Error Margin.
- The center of gravity (CoG)
- The volume
- The moment of inertia (Iox / G)
- The product of inertia (Ixy / G)
- The weight maturity
Tip: You can switch from computed to declared weight by clicking Click this hyperlink to replace computed by declared weight in the information message.

Note: The higher the percentage of weight maturity, the more you can trust your global weight result. For more information, see Weight Maturity.
Close the Weight Definition window.

The tree is updated, reflecting the computed weight status of the assembly using a green rectangle to the left of the assembly's name. The percentage of elements with computed weight is updated.

On leaves, the computed weight information is persistent in the database and accessible using the Properties contextual command. On assembly nodes, this information is accessible in session (not persistent, and thus not accessible with the Properties contextual command).

Example: assembly with weight computed for 80.2% of its parts.


Weight Definition
	Declared		0%
	Computed		80.2%
	Incomplete		19.3%
	Missing		0.4%
	Context		0.2%

Compute the Wet Weight of an Element

You can compute the weight of a part and take its material and the fluid passing through it into account. To compute the dry weight plus the fluid weight, you can use the B.I. Essentials > Weight Definition command.

The fluid weight and the dry weight are automatically available in B.I. Essentials and the Weight and Balance analytics. For more information about the wet weight in secondary analytics, see Weight and Balance User's Guide: Assessing the Weight.

Open a pipe structure in the RFLP Navigator. The Line IDs under the Logical node in the tree and the 3D piping structure under the Physical node must be in session.

Note: When the ID Lines of the pipe are not loaded in session (when you only open the structure), the weight computation does not take the fluid weight into account. Only the dry weight is displayed.
To edit the filling ratio of a pipe, right-click the Line ID and select Properties.
Indicate the fluid contained (for example: oil) and its filling ratio inside the pipe (between 0.0 and 1.0).
To access the B.I. Essentials list, from the Tools section of the Action Bar, click B.I. Essentials . For more information, see B.I. Essentials User's Guide: Using B.I. Essentials.
From the list, select Weight Definition in the B.I. Essentials window.
Click Computed Weight=xxxkg.
The Inertia value window opens in which you can read the computed weight, the inertia matrix, and the center of gravity.
To visualize the weight taking the fluid mass into account (wet weight), click Update .
The wet weight and the inertia matrix are updated.
Notes:
- The weight and the inertia matrix are computed on the dry weight plus the fluid weight.
- The center of gravity is updated only for an assembly in compliance with the mass of each child and, the weighted average is found. But if the center of gravity is updated only for an object, the center of gravity is the same for the pipe with fluid or the pipe without fluid.
Save your product.
To assess the dry weight and the fluid weight of the physical product, click Weight and Balance from the Business Insight section of the action bar. For more information, see Weight and Balance User's Guide: Assessing the Weight.