Creating faces from existing boundaries

Video: Use model cleanup commands in the FEM to close up a solid body

Use the Face from Boundary command to:

• Repair a corrupt or poor quality polygon face that did not tessellate properly when the software created the polygon geometry.When you first create a FEM file, the software creates polygon geometry from the idealized part. The polygon geometry is a one-for-one, faceted (tessellated) representation of your original geometry. Occasionally, the software may encounter problems during this process and may be unable to completely or properly tessellate certain faces. After you use Delete Face to delete the face, you can use the Face from Boundary command to create a new face in that location.

• Create a new polygon face to fill a void in your model.

Defining the boundary of the new face

With the Face from Boundary command, you first use the Select Edges option to select the edges that define the outer boundary of the new face. The edges that you select can be:

• From within the same polygon body or from different polygon bodies.

• Free or non-free polygon edges.

The edges that you select must form a completely closed loop. The software uses asterisks at the ends of edges to indicate an open loop.

If the edges that you initially select with the Select Edges option do not form a closed loop, you can then use the Add Boundary options to add additional straight edges to the selection. Any edges that you select with the Add Boundary options must lie between the end points of the polygon edges you selected with the Select Edges option.

Selecting a body for the new face

When you create a new face with the Face from Boundary command, the software tries to automatically add that new face to the appropriate existing sheet or solid body.

• In general, the software adds the new face to an adjoining sheet body. If there is an adjoining sheet body and an adjoining solid body, the software always adds the face to the sheet body. The only case in which the software adds the face to the solid body instead of the sheet body is when adding the face to the solid body closes a void in the solid.

• In some cases, the software cannot add the newly created face to an adjoining sheet body. For example:If all the selected edges are Face from Mesh edges, then the software cannot add the new face to an adjoining sheet body.If the new face forms a T-junction within the same sheet body. The software cannot add the new face to the sheet body because that would create a non-manifold condition (in which a polygon edge shared by three or more faces from the same polygon body) in the sheet body.

• If the software cannot find a unique solid or sheet body to which to add the face, you must use the Select Polygon Body option to select an adjoining sheet body to which to add the face. You cannot select an adjoining solid body.Note: You cannot use the Select Polygon Body option to select a polygon body that was created either from 2D elements or from 3D element faces.

In such cases, the software creates a new sheet body for the new face and adds that face to sheet body. The new sheet body appears in the Polygon Geometry container in the Simulation Navigator.

Where do I find it?

Application	Pre/Post
Prerequisite	A FEM file as the displayed part and the work part
Command Finder	Face from Boundary
Menu	Insert→Model Cleanup→Face from Boundary

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Related Topics

Generating surface wrap bodies and meshes

Creating faces from existing boundaries, Simcenter 3D 2021.1 Series

© 2020 Siemens

window.mainLanguage="en_US"

window.delivId=""

window.projectId=""

MathJax.Hub.Config({ TeX: { extensions: ["autoload-all.js"] }, tex2jax: { displayMath: [ ] }, "SVG": { scale: 125 } });