Geometry Tutorials(几何学教程)

Turorials

Geometry Tutorials(几何学教程)

HM-2010: Import and Repair CAD(导入和修复CAD)

In this tutorial you will learn how to import and repair CAD.

In addition to importing and repairing CAD, you will:（除了导入和维修CAD，您将）

• Delete untrimmed surfaces(删除未切边的表面)
• Close missing surfaces（关闭未被包括在内的的表面）
• Set the cleanup tolerance（设置清理公差）
• Equivalence free edges（等效自由边）
• Delete duplicate surfaces（删除重复的表面）

The benefits of importing and repairing CAD are:(导入和修复CAD的好处是)

• Correcting any errors in the geometry from import(纠正导入文件的几何学中的任何错误)
• Creating the simplified part needed for the analysis（创建和简化所需的部分为以后的分析）
• Meshing a part all at once（一次画出一个零件）
• Ensuring proper connectivity of mesh（确保网格的适当连接）
• Obtaining a desirable mesh pattern and quality（获得理想的网格图案和质量）

Step1 Open the Model File

In this step you will open and view the model file.

1.Start HyperMesh Desktop.
2.From the menu bar, click File > Open > Model.
3.In the Open Model dialog, open the clip_repair.hm model file.

Step2 View the Model

In this step you will view the model to evaluate its integrity.(在此步骤中，您将查看模型以评估其完整性)

1.Observe where the model has incorrect connectivity and missing or duplicate surfaces.(观察模型哪里有不正确的连接性和缺失或重复的表面)

2.To open the Auto Geometry Cleanup panel, click Geometry > Autocleanup from the menu bar.
The surface edges are now colored according to their topology status. This occurs because Geometry Color is set to .(表面边缘现在根据它们的拓扑状态着色。发生这种情况是因为几何颜色被设置为)

• To display the model’s geometry in wire frame mode, click on the Visualization toolbar.(要在线框模式下显示模型的几何形状，单击可视化工具栏)

**Note: ** The Visualization toolbar contains icons that control the display of the surfaces and surface edges. Surfaces can be shaded with or without edges or wireframe. Right-click the icons to access the drop-down menu for additional options. Place your mouse over the cursor to view a description of the button’s functionality.(可视化工具栏包含控制曲面和曲面边缘显示的图标。表面可以有或没有边缘或线框阴影。右键单击图标以访问下拉菜单以获得其他选项。将鼠标放在光标上，查看按钮功能的描述。)

• To open the Visualization Browser and access the Topology options, click .(要打开可视化浏览器并访问拓扑选项，请单击)
  Note: The Topology options control the display of the surfaces and surface edges. Surfaces can be shaded or wireframe. The check boxes within the Visualization Browser turn the display of the different edge types and fixed points (surface vertices) on or off.(拓扑选项控制表面和表面边缘的显示。表面可以是阴影或线框。可视化浏览器中的复选框可以打开或关闭不同边缘类型和固定点(表面顶点)的显示。)

• Select only the Free check box.(只选择Free复选框。)
  The graphics area displays only the free edges.(图形区域只显示空闲边。)

• Observe the free (red) edges and make note of where they are. Free edges show where there is incorrect connectivity or gaps.(观察空闲的(红色)边，并记下它们的位置。自由边显示哪里有不正确的连接或间隙。)

• Observe the locations where there are closed loops of free edges. These are locations that probably have missing surfaces.(观察有自由边闭合环的位置。这些地方可能没有表面。)

• Select only the Non-manifold check box.(只选中“非流形”复选框。)

• Observe the non-manifold edges and make note of where they are. Non-manifold edges show where there are more than two surfaces sharing an edge, which might indicate incorrect connectivity. For this part, there are yellow edges completely surrounding two areas. This indicates that there are probably duplicate surfaces in these locations.(观察非流形边缘，并记下它们的位置。非流形边表示有两个以上的曲面共享一条边，这可能表明连接不正确。对于这一部分，有黄色的边完全围绕着两个区域。这表明在这些位置可能有重复的表面)
  Select all of the check boxes.
  Close the Visualization Browser.
  To exit the panel, click return.
  To shade the model’s geometry and surface edges, click on the Visualization toolbar.
  To locate any errors in the geometry, rotate, zoom, and pan.
  Note the areas to be worked on:
  A surface that overhangs a round corner
  A missing surface

Step3 Delete a Surface（删除一个表面）

In this step you will delete the surface that overhangs the round corner（在这一步，你将删除悬在圆角上的表面）

1. To open the Delete panel, click Geometry > Delete Surfaces from the menu bar, orpress F2.
2. Optional: If you opened the Delete panel by pressing F2, set the entity selector to surfs.
3. Select the overhanging surface shown in the previous image.
   Click delete entity.
4. HyperMesh deletes the selected entities.
5. To exit the panel, click return

Step4 Create Surfaces to Fill Gaps（创建表面来填充间隙）

In this step you will create surfaces to fill large gaps in the model.（在这一步中，您将创建表面来填充模型中的大间隙）

1. To open the panel from which you can create a surface, click Geometry > Create > Surfaces > Spline/Filler from the menu bar.或者在下面的控制面板（Geom>surfaces>Spline/Filler）Spline/Filler命令的作用：
2. Clear the Keep tangency checkbox.（清除“保持切线”复选框）
3. Set the entity selector to lines.（将实体选择器设置为lines。）
4. Verify the Auto create (free edges only) check box is selected. The Auto create option simplifies the selection of the lines bounding the missing surface. Once a line is selected, HyperMesh selects the remaining free edges that form a closed loop, and then creates the filler surface.（验证“自动创建(仅自由边缘)”复选框被选中。“自动创建”选项简化了对缺少的曲面的边框线的选择。一旦一条线被选中，HyperMesh会选择形成闭环的剩余自由边，然后创建填充面。）
5. Zoom into the area indicated in the following image.（放大到下图所示的区域）
6. Repeat Step 6 to create a filler surface in the other gap.
7. To exit the panel, click return.

Step5 Set Global Geometry Cleanup Tolerance(设置全局几何清理公差/容许偏差)

In this step you will set the global geometry cleanup tolerance to .0.1.(在此步骤中，您将设置全局几何清理公差为.0.1。)

1. Press O to open the Options panel.(按O打开选项面板。)
2. Go to the geometry subpanel.(转到几何子面板。)
3. In the cleanup tol = field, type 0.01 to stitch the surfaces with a gap less than 0.01.(在清理工具=字段中，键入0.01以缝合间隙小于0.01的表面。)
4. To exit the panel, click return.

Step6 Combine Multiple Free Edge Pairse(组合多个自由边对)

In this step you will combine multiple free edge pairs at one time with the equivalence tool(在这个步骤中，你将使用等价工具一次组合多个自由边对)

1. From the menu bar, click Geometry > Edit > Surface Edges > Equivalence.
2. Select the equiv free edges only check box.(check box 就是一个复选框)
3. Select surfs >> all.
4. Verify that the cleanup tol= is set to 0.01.（检查清理工具）
   This is the global cleanup tolerance that you specified in the Options panel.（这是您在选项面板中指定的全局清理容错。）
   5 .Click equivalence.
   HyperMesh combines any free edge pairs within the specified cleanup tolerance. Most of the red free edges are combined into green shared edges. The few remaining are caused by gaps larger than the cleanup tolerance.（HyperMesh在指定的清理容限内组合任何空闲的边对。大部分红色的自由边被合并成绿色的共享边。剩下的几个是由大于清理容忍度的间隙造成的。）

Step7 Combine Free Edge Pairs Using the Toggle(使用切换组合自由边缘对)

In this step you will combine free edge pairs, one pair at a time, usingthe toggle.（使用切换组合自由边缘对）

1. Go to the toggle subpanel. （转到切换子面板。）
2. In the cleanup tol= field, type 0.1.（）
3. Click one of the free edges shown in the following image. When you select the edge, it will change from red to green, indicating that the free edge pair has been equivalenced.（点击下图中显示的一条空闲边。当你选择边时，它会从红色变为绿色，表明自由边对已经等效）
4. Use toggle to equivalence the other edges shown in the previous image.（使用切换来等效于前面图像中显示的其他边。）

Step8 Combine Free Edge Pairs Using Replace（用Replace命令组合边对）

In this step you will combine the remaining free edge pairs using replace.（在这一步中，你将使用replace来组合剩余的自由边对。）

1. Go to the replace subpanel.
2. In the Model Browser, View folder, right-click on View2 and select Show from the context menu.（在Model Browser, View文件夹中，右键单击View2，并从上下文菜单中选择Show。）
   The graphics area displays two edges to retain and remove for replacement.（图形区显示两条边，保留和移除以供替换）
3. With the moved edge line selector（对话框） active, click the left most free edge.（当移动的边缘线选择器处于活动状态时，单击最左边的空闲边缘。）
4. With the retained edge line selector（对话框） now active, select the rightmost red edge.（保留的边缘线选择器现在处于活动状态，选择最右边的红色边缘。）
5. In the cleanup tol= field, type 0.1.
6. Click replace.
   HyperMesh posts a message similar to, “Gap = (.200018). Do you still wish to replace?”
7. To close the gap, click Yes.
8. To exit the replace subpanel, click return.

Step9 Find Duplicate Surfaces（发现重复的表面）

In this step you will find and delete all duplicate surfaces.（在这一步，你将找到并删除所有重复的表面。）

1. From the menu bar, click Geometry > Defeature > Duplicates.
2. Click surfs >> displayed.
3. In the cleanup tol= field, type 0.01.
4. Click find.
5. The status bar displays the following message, “2 duplicated surfaces were found.”（状态栏显示如下消息，“发现了2个重复的表面”。）
6. To remove duplicate surfaces, click delete.

Step10 Observe Free Edges or Duplicate Surfaces（观察自由边或重复表面）

In this step you will observe the model to identify any remaining free edges, or missing or duplicate surfaces.（在此步骤中，您将观察模型，以识别任何剩余的自由边，或缺失或重复的表面。）

1. On the Visualization toolbar, change the geometry color mode to and click to shade the model’s geometry and surface edges.（在可视化工具栏上，更改几何颜色模式为，并单击以阴影模型的几何和表面边缘。）
2. Observe the model again to identify the remaining free edges and missing or duplicate surfaces.（再次观察模型，以识别剩余的自由边缘和丢失或重复的表面。）

Note: All of the edges in the model should be displayed as green shared edges, indicating that you have a completely enclosed thin solid part.
To exit the return panel, click return.（模型中所有的边都应该显示为绿色的共享边，这表明你有一个完全封闭的薄实体部分。
要退出返回面板，单击return。）

总结:

• 自由边是红色
• 共享边是绿色
• 压缩边是蓝色
• 有三个面的共享边是？

下面分别介绍各几何特征的含义。

（1）Surface（曲面）

1）Free edges(自由边）：没有与其它任何曲面相连接的单独的边，即此边在拓扑关系上仅属于一个曲面。

2）Shared edges（共享边）：由两个曲面共同拥有的边。

3）Suppressed edges（抑制边）：共享边被手工抑制。这样在自动划分网格时，会将两个共享一条抑制边的曲面认定为一个曲面进行网格划分。这样所划分的网格可以穿过抑制边，同没有抑制边的效果一样。

4）T-junctions(T型边）：被三个或三个以上的曲面共享的边。

（2）3D solids（3D实体）

1）Fin faces：用于切割3D实体对象的面，但是该面对实体只进行了部分切割，即该曲面没有完全延伸至整个实体。

2）Bounding faces：实体对象的表面边界面。

3）Full partition faces：相邻实体间的面。

4）2D faces（topo）：使用2D 拓扑显示（by 2D topo）的显示模式时，显示的是不属于实体的2D曲面拓扑关系的颜色。

5）Ignored（topo）：使用2D 拓扑显示（by 2D topo）的显示模式时，显示的是2D曲面的颜色。

6）Edges（topo）：组件模式（by comp）显示下，代表网格边界线。

（3）By mappable display mode（solids）（映射显示模式下的实体）

1）1 dir.map（单方向映射）：划分3D网格时可在一个方向上进行映射的实体显示。

2）3 dir.map（三方向映射）：划分3D网格时可在三个方向上进行映射的实体显示。

3）Not mappable：已经被编辑过但是仍需要继续切分才能变为可映射的实体显示。

4）Ignored map：需要进行再次切分变成可映射模式的实体显示。

以上几何特征根据维度分为2D曲面和3D实体两类，两类几何特征之间互不影响。第三类By mappable display mode（solids）不针对具体的几何实体，而用于标明实体的几何特征，且仅在可映射的（mappable）几何显示模式下有效，在其它显示模式下，不会有这些颜色的区分。

HM-2020: Generate a Midsurface (生成一个中面)

In this tutorial you will generate a midsurface.(在本教程中，您将生成一个中面)

In this tutorial you will learn how to

• Create a midsurface(创造一个中面)
• Visualize the midsurface by using shading options and transparency(通过使用阴影选项和透明度来可视化中间表面)

This exercise uses CAD geometry data for a thin solid clip. Because of the small thickness of the part, it is assumed that it will be modeled for FEA as shell elements. The elements will be created on the mid-plane of the part.(本练习使用CAD几何数据制作一个薄的实心夹。由于零件的厚度较小，故假定其在有限元分析中为壳单元。这些元素将被创建在零件的中间平面上。)

In this exercise you will use the clip_midsurface.hm model file, which can be found in the hm.zip file. Copy the file from this directory to your working directory.

The surfaces in this model have no connectivity errors. This could be because the file was imported without errors or because the errors were corrected using HyperMesh. In this case, errors in the topology were repaired in the previous exercise (missing surfaces are re-created, duplicate surfaces are deleted, gaps are closed, and so on). For this tutorial, you can continue using the model you created in the previous tutorial, or you can open the new, clip_midsurface.hm, file. Either way, the geometry is at the point where you can use the Midsurface panel to generate a midsurface.(该模型中的曲面没有连通误差。这可能是因为文件导入时没有错误，也可能是因为使用HyperMesh纠正了错误。在这种情况下，在前面的练习中修复了拓扑中的错误(丢失的表面被重新创建，重复的表面被删除，间隙被关闭，等等)。对于本教程，您可以继续使用您在上一教程中创建的模型，或者您可以打开新的clip_midsurface。嗯,文件。无论哪种方式，几何图形都在您可以使用Midsurface面板来生成一个中间表面的点上。)

step1 Open the Model File

In this step you will open and view the model file.

1. Open the clip_midsurface.hm model file.
2. On the Visualization toolbar, click to shade the model’s geometry and surface edges, and click to change the geometry color mode to mixed. The surfaces displayed in the graphics area represent a solid part.(在可视化工具栏上，单击为模型的几何和表面边缘着色，单击将几何颜色模式更改为混合。在图形区显示的表面代表一个实体部分。)

Note: These visualization techniques will be necessary for viewing the newly created midsurface.(这些可视化技术将是必要的，以查看新创建的中间表面。)

step2 Generate a Midsurface ()

In this step you will generate a midsurface from the midsurface panel.（在这一步中，您将从中间功能上面板生成一个中间表面）

1. From the menu bar, click Geometry > Create > Midsurfaces > Auto.
2. Verify that the closed solid option is selected, and the entity selector is active and set to surfs.(确认关闭的实体选项已被选中，并且实体选择器处于活动状态并设置为surfs。)
3. Select one surface.
4. To start the midsurface generation, click extract.
   HyperMesh creates the midsurface, and organizes the surfaces into a new Middle Surface component. When HyperMesh creates the midsurface, transparency is turned on for all of the other components in the model except the new Middle Surface component.（HyperMesh创建了中间表面，并将这些表面组织成一个新的中间表面组件。当HyperMesh创建中表面时，模型中除了新的中表面组件之外的所有其他组件的透明度都是打开的）

step3 Review the Midsurface(检查Mid-surface)

In this step you will review the part’s midsurface.(在这一步中，你将检查零件的中间表面)

1. in the Model Browser, only display the Middle Surface component. The graphics area displays the midsurfaces generated for the solid sections of the model using the auto-midsurface panel.(在模型浏览器中，只显示Middle Surface组件。图形区域显示了使用自动中间面板为模型的实体部分生成的中间表面。)
2. In the Model Browser, turn the geometry for the lvl10 component back on.(在模型浏览器中，重新打开lvl10组件的几何图形。)
3. To open the Transparency panel, click on the Visualization toolbar.(要打开透明度面板，单击可视化工具栏)
4. With the comps selector active, select a line or surface of the lvl10 component.
   HyperMesh selects the entire component because the entity selector is set to comps.
   Note: You may need to zoom in on the model to select a valid entity.
5. Under transparency, click several times.
   The surfaces in the lvl10 component become more and more transparent.
6. Optional: Drag the transparency slider back and forth to control the level of transparency.
7. To visualize the midsurface, rotate, zoom, and pan.

step4 Save Your Work

In this optional step you will save your work.

Now that the midsurface has been created, it is a good time to save the model.

Optional: From the menu bar, click File > Save > Model.
You have now created surfaces on the mid-plane of the part. These surfaces can now be meshed or further modifications can be made to their topology, depending on the requirements of the analysis.

HM-2025: Auto-Midsurface with Advanced Extraction(自动中层与高级提取)

In this tutorial you will use auto-midsurfacing with advanced extraction options.
You will learn how to:

• Use the offset+planes+sweeps option when midsurfacing（在中表面时使用偏移+平面+扫描选项）
• Manually correct gaps in an auto-generated midsurface using the plates edit function（手动纠正间隙在一个自动生成的中间面使用板编辑功能）
  In this tutorial, you will be using CAD geometry data for a box with thin ribs inside of it. Because the geometry consists of thin planar sections, it is assumed that it will be modeled for FEA as shell elements. The elements will be created on the mid-planes of each section.（在本教程中，您将使用CAD几何数据创建一个内部有薄肋的盒子。由于几何结构由薄的平面截面组成，因此假定它将在有限元分析中建模为壳单元。元素将被创建在每个部分的中间平面上）

This exercise uses the Insert_planes.hm file, which can be found in the hm.zip file. Copy the file from this directory to your working directory.

step1 Open the Model File

1. Start HyperMesh Desktop.
2. From the menu bar, click File > Open > Model.
3. In the Open Model dialog, open the Insert_planes.hm model file.
4. From the menu bar, click Geometry > Create > Midsurfaces > Auto.
5. In the Auto Midsurface panel, click the toggle and select closed solid.
6. Select any surface.
7. Click extraction options.
8. From the drop-down menu, select offset+planes+sweeps.
9. Go to the auto extraction subpanel.
10. Click extract.
11. Shade the model’s geometry and surface edges by clicking on the Visualization toolbar.
12. Review the generated midsurface by hiding the Body.1 component in the Model Browser.
    Some of the plates do not properly cross.

step2 Resolve Midsurface Gaps

In this step you will use the edit plates subpanel to resolve midsurface gaps.(在这一步中，您将使用编辑板子面板来解决表面中间的间隙)。

1. In the Model Browser, display the component Body.1.
2. On the Visualization toolbar, set the geometry display mode to .
3. From the panel area, select the interim edit tools from the drop-down
   From the edit plates subpanel, clickshow/edit all.
   HyperMesh populates the Model Browser with plates that were detected by the tool.

Note: If you have not yet extracted the middle surface using either the offset+planes or offset+planes+sweeps options, then the model will not have any plate information yet. Plate components will not be populated in this situation.(如果你还没有使用偏移+平面或偏移+平面+扫描选项提取中间表面，那么模型将没有任何板块信息。在这种情况下，板块组件将不会被填充。)

4. In the Model Browser, hide the components Body.1 and Middle Surface.
5. Verify that the full plate surfs selector is active.（确认全板曲面选择器处于激活状态。）
6. Select the green face.
7. HyperMesh selects all of the plates in the ^Planar plate #0 component.
8. Hide all of the plates in the ^Planar plate #0 component by right-clicking on the same face.
9. Hide the three remaining exterior sides.(隐藏剩下的三个外部面)
   HyperMesh hides the components ^Planar plate #2, ^Planar plate #3, and ^Planar plate #4.(HyperMesh隐藏了^Planar plate #2、^Planar plate #3和^Planar plate #4组件。)
10. Select any face from the long interior rib, as shown in the following image. This rib was split into three groups by the algorithm and needs to be reunited into one component.(从长内肋选择任何面，如下图所示。这个肋骨被算法分成了三组，需要重新组合成一个组件)
11. Select the two remaining plates from the long interior rib
12. Merge the three plates into a single planar plate by setting the plate type to planar.（通过将板块类型设置为平面，将三个板块合并为一个平面板块。）
13. Click merge plates or middle-click in the graphics area.
    HyperMesh combines the three plates into a single component and displays them in the same color.
14. Using the full plate selector, select the newly created plate.
15. Click the single surface selector.
    The selected plate is isolated, and one side is colored blue while the other side is colored green.
16. Review the isolated plate by toggling non-plates off/non-plates on to non-plates off.
17. Notice the long narrow surface that displays with the left-most plate. Select it with the single plate selector and set it to plate edge
18. Click the full plate selector to recover the view you had before isolating and reviewing the plate, and hide the plate sides shown in blue and green.
19. Merge the two remaining internal ribs.
20. Click update.
21. Click return.
22. Review the generated midsurface by hiding the Body.1 component in the Model Browser. The plates are closer together but they are still not the full length of the rib due to the holes that trim the plates.（通过在模型浏览器中隐藏Body.1组件来查看生成的中间表面。钢板之间的距离更近了，但由于钢板上的孔洞，它们仍然不是肋骨的全长。）

step3 Use Plates Edit

In this step you will use plates edit to resolve remaining gaps.

1. In the interim edit tools panel, edit plates subpanel, click show/edit all.
   HyperMesh populates less plate components in the Model Browser because some plates were merged in the previous steps.
2. Hide all components except ^Plate edge.
   Using the single surface surfs selector, select all four internal surfaces of the two holes
   Note: Each hole has two internal surfaces.（使用单一表面选择器，选择所有四个内表面的两个孔

注:每个孔有两个内表面。）
4. Click not a trim surface.
HyperMesh organizes the selected surfaces into a new component labeled ^Not a trim surface.（只留下^Plate edge层。使用single surface selector，选中单独的面，告诉hypermesh它们不是用来修剪的。点选两个面，单击 not a trim surface。）
5. Click update.
6. Click return.
7. Review the generated midsurface by hiding the Body.1 component in the Model Browser. There is now a yellow edge where the plates meet, which indicates that the plates are intersected correctly. It would have been possible to reorganize the plates and create the Not a trim surface component at the same time.（通过在模型浏览器中隐藏Body.1组件来查看生成的中间表面。现在在板块相交的地方有一条黄色的边，这表明板块相交正确。这将有可能重新组织板和创建一个不修剪的表面组件在同一时间。）

step4 Save Your Work

In this optional step you will save your work.

This step is optional.

Optional: From the menu bar, click File > Save > Model.
The model now contains surfaces on the mid-plane of the part. You used insert planes and plates edit to ensure that there were no erroneous gaps in the generated midsurfaces. You can now mesh these surfaces, or further modify their topology, depending on the requirements of the analysis.（模型现在包含了零件的中间平面上的表面。你们使用了插入平面和板块编辑，以确保生成的中间表面没有错误的间隙。现在，您可以根据分析的需求对这些表面进行网格化，或者进一步修改它们的拓扑结构。）