COMSOL 6.2 - Detect Interferences

To analyze the interference of geometry objects, from the toolbar, (

) menu, select (

). You can also right-click the node and select the same option from the context menu.

When you are in the window for , you can at any time switch to another defeaturing tool by clicking one of the corresponding buttons at the top of the window.

In the list, select the objects you want to analyze. In the text field, enter the absolute tolerance, which has the default value of 0.1 mm, to be used for the search. When you click the button, a list of interferences is displayed in the list.

The interference detection applies to the exterior faces of the selected objects, thus ignoring interior faces, isolated edges and vertices. Each detected interference involves two objects. The following types of interferences appear in the list when detected by the tool:

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Touch. Two interfering objects are classified as touching when they intersect, and the interfering faces are located within a distance less than the specified tolerance from each other. Thus, an intersection (as defined below) may become a touch after you increase the tolerance such that it becomes larger than the distance between the interfering faces.

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Intersection. An intersection between the two objects is detected, and the interfering faces are located at a distance that is larger than the tolerance from each other.

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Gap. No intersection is detected between the two objects, but they have faces with portions that are located within a distance less than the specified tolerance from each other. The detected size of the gap appears in the list.

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Containment. One object is a contained in another object, which is a solid.

By default the list displays the detected interferences in a tree with the interferences as the top level nodes sorted by the type of interference. To sort the list by the objects select the check box. In this case the objects involved in an interference are listed as the top level nodes in the tree. Expand a top level node to see the list of objects that the object on the top level is interfering with. Expand a subnode to see the list of detected interferences for the objects. You can expand the nodes for the detected interferences to reveal the two interfering objects, and then expand the nodes for the objects to look at the interfering faces displayed in subnodes according to the following:

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For two intersecting solid objects the nodes for the objects have two subnodes each, Inside and Outside. Click the Inside node to highlight the parts of the interfering faces that are inside the other object. Click the Outside node to highlight the parts of the interfering faces that are outside the other object.

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For two intersecting surface objects the nodes for the objects have two subnodes each, Small side and Large side. The faces resulting from the intersection are grouped according to size since surface objects do not delimit a volume in space, thus it is not possible to determine what is inside or outside the other object. Click the Small side and Large side nodes to highlight the parts of the interfering faces that result from the intersection with the faces of the other object.

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For an intersection of a solid and a surface object, the node for the solid object has the subnodes Small side and Large side, while the node for the surface object has subnodes Inside and Outside.

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For two touching objects, the nodes for the objects may have two subnodes, Touching and Not touching. Click these nodes to highlight the corresponding portions of the interfering faces.

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For a gap between two objects, the nodes for the objects may sometimes have two subnodes Touching and Not touching.

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For a Containment node, the first subnode is the containing object, and the second subnode is the contained object.

Visualization of Detected Interferences

For a better visualization of the detected interferences, the Detect Interferences tool partitions the faces involved in the intersections and touches so that the interfering face regions can be shown and highlighted separately. In the list, when you select the nodes for the interferences, or the topmost or first sublevel object nodes when the check box is selected, the interferences are visualized only by highlighting those faces or face regions that enclose an intersection or are directly in touch. In the list, these are the faces belonging to the first subnode of each object node under the selected interference node. Thus, when you click a node for an interference in the list, the faces or face regions belonging to nodes Outside, Large side, and Not touching are not highlighted. Expand the node for the interference, and select the object subnodes, to see highlighted the involved faces in their entirety, including the face regions that are not directly interfering.

Note that the face partitioning that is the result of the intersections is visible only while working with the Detect Interferences tool, and that the geometry is not modified by this tool.

To change which objects are shown in the Graphics window while selecting nodes in the list choose one of the options from the list:

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Choose to show only the interfering faces involved in the selected node. For example, if you select an intersection node from the list, only the face regions from the two objects that are involved in the intersection are shown.

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Choose (default) to show only the objects involved in the selected node.

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Choose to show the object that is interfering with the currently selected object subnode to the interference node.

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Choose to show both objects involved in an interference when you select one of the subnodes to the interference node.

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Choose to show all objects regardless of which nodes are selected.

The button next to the list may also help to find the detected interferences on the geometry. For a better view of the interferences between objects you can also click the or buttons in the Graphics toolbar.