Intersect Surfaces

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The actions in the Surface Intersection menu can be used to manipulate or generate surface geometry based on intersections with other surfaces (i.e., meshes or grids). The output will be in the form of new surfaces - the originals are not modified. Any number of surfaces (at least two) can be intersected at once. These tools are helpful for creating new geometry for use in modeling, but they are also important to ensure that model volumes are well-formed (i.e., clearly bounded and with no negative volumes).


These intersection tools do not constrain the "quality" of the output triangles. Although finite element analysis requires well-shaped triangles, all surface geometry used in SVOffice will be automatically re-meshed regardless, and therefore triangle aspect ratios should not be of concern in SVDesigner.




It is not always possible to guarantee a solution for a given intersection problem, depending on the current mesh settings and the complexity of the input surfaces. We recommend saving your conceptual model before continuing.
Be patient when intersecting large meshes, as the calculations may be very complex.


There are a few common terms used here, defined as follows:


Subject Surfaces:These are the surfaces to be modified by the action in question. Generally, each subject surface will have a corresponding modified output surface after the action is complete.


Clipping Surface:This is the surface used as input to the action in question. It will not be modified by the action, but in some cases, the user can request an updated version of the clipping surface; for example, a new version containing additional mesh points to match surface being intersected with it.


Intersection Profile:This term refers to the set of line segments formed by the intersection between surfaces. These segments are grouped into closed polylines where possible, and open polylines otherwise. Upon output, some actions can generate regions and polylines of intersection automatically.


There are two general-purpose intersection actions that can be run manually by the user:


Fix Intersecting Geometry


This action does not modify surface shape, but rather it splits triangles where needed such that no triangles in any of the selected surfaces intersect each other (they will instead have shared segments where they used to intersect). This lack of triangle intersection is a requirement for volume meshing in SVOffice. Note that every other intersection tool used below implicitly performs this action as part of its operation, so it is not normally needed to use this explicitly. The exception is that this tool should be used when the output of one of the other intersection tools results in a warning that further intersections are needed.


Create Regions from Intersection Profiles


This action does not modify the surfaces in any way - instead, it outputs regions that define the lines of intersection between the surfaces (if any). If an intersection profile does not define a closed shape, it will be output as a polyline instead.


This action can be performed as part of any of the other actions described below, as an option available in the surface intersection dialog.