The Onshape Mass properties tool is available in Part Studios and assemblies. Find the Mass properties tool in the bottom-right corner of the desktop interface or on the main mobile toolbar.

また、このツールを使用してプロパティをオーバーライドし、質量に独自の値を指定することもできます。

Example of location of Mass and section properties tool

Properties are additive: for each additional part you select, its properties are added to the calculations in the dialog (desktop) or panel (iOS and Android). When you apply materials to parts, the density of the material is used in the calculations in the Mass and section properties dialog/panel. If a part has no material assigned, no figure for that part is used in the calculation (and a note is displayed in the dialog/panel to that effect).

質量特性の計算結果は概算です。プロパティの計算は、ジオメトリの複雑さに応じて精度が異なる場合があります。

Enabling Show calculation variance displays the value and the difference between the lower and upper bound of the calculated value. If Show calculation variance is not enabled, the computed value without the bounds is displayed. The computations of the values are not affected by the state of the Show calculation variance checkbox.

パーツリスト （またはグラフィック領域） のパーツのコンテキストメニューから材料 をパーツに適用します。

The Mass properties tool allows you to view and override mass, volume, surface area, center of mass, and inertia for parts in Part Studios and assemblies. First, parts must have a material assigned to them. Right-click the part and select Edit material. Then assign a pre-made material from the library or select Custom and enter values. The density of the material is used in the mass properties calculations. Next, click the Mass properties tool at the bottom right corner. Select the parts to include in the calculations. If a part has no material assigned, it is not used in the calculations and displays red (for example, the Spindle here). Properties are additive: each additional part selected adds to the calculations in the dialog. Click the red x to exit the Mass properties dialog.

Mass properties are also available from assemblies. Click the Mass properties tool and then select the parts to make up the calculations. Click the red x to exit the dialog.

  1. To open the Mass and section properties dialog, click the small scale icon 質量特性ツールアイコン in the bottom-right corner of the interface.

    グラフィック領域で選択を行い、質量特性ダイアログを表示する

  2. Select either the Part tab to get the mass properties for an entire part(s) or the Face tab to get the mass properties for a cross section or face(s).
  3. グラフィック領域で選択を行います。

    4. The center of mass is marked with on the model when the Mass and section properties dialog is open, as shown in the image above and in the image below.

  4. If you wish to override calculations and enter your own mass values, select the entire part or assembly in the Features or Instances list on the left. Then, check the Override box and enter the desired value. Appropriate recalculations are made once a new value is entered.

    質量の計算を上書きする例

交差したパーツの場合、プロパティは個別のパーツ全体を計算した後に合計します。

The Mass and section properties dialog provides the following information, presented from top down as shown in the tool:

  • Parts/faces/instances to measure - Click a face or part in the graphics area or Features/Instances list to add it to the calculations.
  • Select a mate connector, inferred or existing (optional), to calculate the moments ofiInertia more accurately (instead of to the common centroid of the selected parts):

質量特性ダイアログで合致コネクタを選択する値の使用例

  • Mass of all parts that have a material applied
  • すべての選択したパーツのボリューム
  • Surface area of all selected parts or faces
  • Perimeter of all selected faces
  • マテリアルを適用したすべてのパーツの重心
  • Moments of inertia
    • Calculated with respect to the common centroid of the selected parts/faces (not the Part Studio/assembly origin)
    • For parts, calculated using the densities of the assigned materials assigned. Any selected parts without materials assigned are omitted from the calculation. If no materials are assigned to any selected parts, no calculation is made.

You can use the information shown in the Mass and section properties dialog to enter values elsewhere in the system (for example, as a dimension).

  1. With the Mass and section properties dialog expanded, click the value to view and highlight the max precision.

  2. Click again to toggle the view to value with default decimal place setting.

Use native shortcut keys to copy values to the clipboard.

オレンジ色の丸で囲まれた質量特性ツールアイコン

オレンジ色の丸で囲まれた質量特性ツールアイコン

計算をオーバーライドし、[質量] に独自の値を入力する場合は、左側の [インスタンス] リストでアセンブリ全体を選択します。次に [質量オーバーライド] ボックスにチェックを付け、所定の値を入力します。新しい値が入力されると、適切な再計算が行われます。

質量特性ダイアログでオーバーライドを有効に切り替える

  • To use the Mass properties tool; either select the tool and the parts/faces/instances to measure. You can also select the parts/faces first, then select the tool.
  • You can select multiple parts/faces at a time.
  • Parts and faces may be selected in both the graphics area and the Features, Parts, and Instances lists.

[質量特性] ダイアログには、次の情報が表示されます。これらの情報はダイアログ内で上から下に表示されます。

情報は、ドキュメントに設定した既定の単位で表示されます。上の図は、質量特性情報をインチ (このドキュメントの既定の単位) で表示しています。
ドキュメントの既定の単位を変更するには、左上のドキュメントメニューアイコンをタップし、単位を選択し、必要な長さ、角度、質量を選択します。

  • Parts/faces/instaces to measure - Tap to view the list of selected entities. Swipe left on an entity in the list to reveal a delete option.
  • マテリアルを適用したすべてのパーツの質量
  • すべての選択したパーツのボリューム
  • Surface area of all selected parts or faces
  • Perimeter of all selected faces
  • マテリアルを適用したすべてのパーツの重心
  • Moments of inertia
    • Calculated with respect to the common centroid of the selected parts/faces (not the Part Studio/assembly origin)
    • For parts, calculated using the densities of the assigned materials assigned. Any selected parts without materials assigned are omitted from the calculation. If no materials are assigned to any selected parts, no calculation is made.

If you select more than one part/face at a time, the combined properties of the parts/faces are calculated. Any intersecting parts/faces have the properties of each individual whole part/face calculated and added together.

If you want to override calculations and enter your own values for Mass, select the entire part, face, or assembly, then check the Mass Override box and enter the desired value. Appropriate recalculations are made once a new value is entered.

赤の丸で囲んだ質量特性ツールアイコンの例

Android アプリケーションの Part Studio ツールバーに表示される質量特性ツール

赤の丸で囲んだ質量特性ツールアイコンの例

Android アプリケーションの [アセンブリ] ツールバーに表示される質量特性ツール。

  • [質量特性] ツールを使用するには、ツールを選択してからパーツを選択するか、最初にパーツを選択してからツールを選択します。
  • You can select multiple parts/faces at a time.
  • Parts and faces may be selected in both the graphics area and the Parts/Features/Instances lists.

アセンブリで使用中の質量特性ツールの例

[質量特性] ダイアログには、次の情報が表示されます。これらの情報はダイアログ内で上から下に表示されます。

情報は、ドキュメントに設定した既定の単位で表示されます。上の図は、質量特性情報をインチ (このドキュメントの既定の単位) で表示しています。
ドキュメントの既定の単位を変更するには、左上のドキュメントメニューアイコンをタップし、単位を選択し、必要な長さ、角度、質量を選択します。

  • Parts/faces/instances to measure - Tap to view the list of selected entities. Swipe left on an entity in the list to reveal a delete option.
  • マテリアルを適用したすべてのパーツの質量
  • すべての選択したパーツのボリューム
  • Surface area of all selected parts or faces
  • Perimeter of all selected faces
  • マテリアルを適用したすべてのパーツの重心
  • Moments of inertia
    • Calculated with respect to the common centroid of the selected parts/faces (not the Part Studio/assembly origin)
    • For parts, calculated using the densities of the assigned materials assigned. Any selected parts without materials assigned are omitted from the calculation. If no materials are assigned to any selected parts, no calculation is made.

If you select more than one part/face at a time, the combined properties of the parts/faces are calculated. Any intersecting parts/faces have the properties of each individual whole part/face calculated and added together.

If you want to override calculations and enter your own values for Mass, select the entire part, face, or assembly, then check the Mass Override box and enter the desired value. Appropriate recalculations are made once a new value is entered.