The term "web cutting" refers to the act of cutting an existing body or bodies, referred to as the "blank", into two or more pieces through the use of some form of cutting tool, or "tool". The two primary types of cutting tools available in Trelis are surfaces (either pre-existing surfaces in the model or infinite or semi-infinite surfaces defined for web cutting), or pre-existing bodies.
The various forms of the web cut command can be classified by the type of tool used for cutting. These forms are described below, starting with the simplest type of tool and progressing to more complex types.
The primary purpose of web cutting is to make an existing model meshable with the hex meshing algorithms available in Trelis. While web cutting can also be used to build the initial geometric model, the implementation and command interface to web cutting have been designed to serve its primary purpose. Several important things to remember about web cutting are as follows:
- The geometric model should be checked for integrity (using imprinting and merging) before starting the decomposition process. This makes the checking process easier, since there are fewer bodies and surfaces to check. Once the model passes that initial integrity check, it is rare that decompositions using web cut will result in a model that does not also pass the same checks.
- The use of the Imprint option can in cases save execution time, since it limits the scope of the imprint operations and thereby works faster. The alternative is performing and Imprint All on the pieces of the model after all decompositions have been completed; this operation has been made much faster in more current releases of Trelis, but will still take a noticeable amount of time for complicated models.
- While the web cut commands make it very simple to cut your model into very many pieces, we recommend that the user restrict the decomposition they perform to only that necessary for meshability or for obtaining an acceptable mesh. Having more volumes in the model may simplify individual volumes, but may not always result in a higher quality mesh; it will always increase the run time and complexity of the meshing task.
- When the web cut command is executed the associated geometry will be regularized. This behavior can be changed, see geometry booleans.
- Web cutting volumes will automatically separate parent bodies as well. This behavior can also be changed, see Separating Multi-Volume Bodies.
- If a geometric entity got split after the webcut operation, then the notesets/sidesets/blocks applied on that initial geometric entity will be carried over to the split entities.
The Decomposition Tutorials and the Power Tools Tutorial contain some examples that demonstrate the use of web cutting operations.