specifies the tolerance used in operations where topology is automatically calculated.

resets the topology tolerance to the default value. The default topology tolerance will be set to the smaller of:

is the distance allowed between the triangle edge and the actual surface edges. Ansys ICEM CFD triangulates Bspline surfaces and curves when it reads Tetin files. A very low tolerance will give a good representation of the geometry but will require more memory and longer processing time. A higher tolerance will give good performance and less memory usage but a coarser representation of the geometry.

A coarser geometry representation may be a better choice for a large model that will be coarsely meshed. For example, a bigger triangulation tolerance would be reasonable for a full engine assembly model that is going to be shrinkwrapped. If fine precision is required, you may choose a finer triangulation tolerance. For example, some geometry operations, such as trimming a curve with a curved surface will be affected. Also, users who generate very thin boundary layers on curved surfaces may have issues if their surface curvature is not being adequately represented.

An optimal value for most models is 0.001. This setting is independent of the mesh element size.

In the examples below, note that for every 1/10^th reduction in the Tri Tolerance, each square of the surface representation is further divided into 12-16 squares.

is a factor of the minimum edge length of a given surface or curve. If enabled, the triangulation tolerance is calculated using this factor for each surface. If disabled, the triangulation tolerance is in actual units.

allows you to select the appropriate units of length for your model. The default selection is Unitless, where you need to ensure that the intended proportions are reasonable. In this case, you can use the Measure Distance ( ) tool to make sure the model appears to be of the right scale.

allows you to draw the entire geometry and blocking to scale based on the selected Length Units. Click Apply to scale the model. This options has no effect if Unitless is selected.

allows you to include mesh sizes when drawing to scale based on the selected Length Units. Default is off. This option requires Scale to selected unit to be enabled.