triangle refinement
The triangle refinement module is primarily for use with distance to surface. It can subdivide triangular and quadrilateral cells until none of the sides of the output triangles exceed a user specified length (a default value is calculated as 5% of the x-y extent of your input surface). This increases the accuracy of distance to surface especially when the input surface comes from create tin and the nodes used to create the TIN are poorly spaced. It can also correct the normals of a surface. It does this by organizing all of the triangles and quadrilaterals in a surface into disjoint patches, and then allowing the user to select which patches have normals that need to be flipped. The maximum number of triangles in a patch is 130,000; any triangles above this number will be considered to be in the next patch.
Removing small cells is used to remove extremely small cells (based on area in your coordinate units squared) that sometimes are generated with CAD triangulation routines that might have their normal vectors reversed and would contribute to poor cutting surface definition. Try this option if you find that distance to surface is giving anomalous results.
The ability to fix normals is used to check that all of the triangles in selected patches of the surface have the same normal vector direction. If the normal is backwards, you can flip the normal of the patch in two ways. The first way is Alt + Right click on a cell in the patch that you wish to flip and then click the Add patch to flip list button. You only need to do this for one cell in each patch. Another way to do this is to set the Cell ID and Cell Data value of a cell in the patch you wish to flip. The Cell Id and Cell Data values must be obtained from the surface being output from triangle refinement, and not the surface being input.
Ports
| Direction | Name | Type | Description |
|---|---|---|---|
| Input | Input Field | Field | A field of triangles. |
| Output | Output Field | Field | A field containing the altered triangles. |
| Output | SampleData | Renderable | A renderable object displaying the input triangles with assigned cell data. |
Properties
| Property | Type | Description |
|---|---|---|
| Execute | Button | The Execute button will force the module to run with the current settings. |
| Remove Coincident Nodes | Boolean | The Remove Coincident Nodes toggle is used to merge nodes that have multiple nodes occupying the same coordinate space. |
| Remove Small Area Cells | Boolean | The Remove Small Area Cells toggle is used to remove extremely small cells (based on area in your coordinate units squared) that sometimes are generated with CAD triangulation routines that might have their normal vectors reversed and would contribute to poor cutting surface definition. |
| Small Area Value | Double | If Remove Small Area Cells is selected the Small Area Value is the cut off value. |
| Split Cells | Boolean | The Split Cells toggle is used to ensure that none of the triangles have an edge longer than the maximum edge length. |
| Maximum Edge Length | Double | The Maximum Edge Length value allows the maximum length of each triangle side to be set for when the Split Cells toggle is set. |
Triangle Normal Settings
| Property | Type | Description |
|---|---|---|
| Fix Normals | Boolean | The Fix Normals toggle is used to check to make sure all of the triangles in selected patches of the surface have the same normal. If the normal is backwards, you can flip the normal of the patch by Ctrl + Left clicking on a cell in the patch that you wish to flip and then adding the patch to the flip list using its cell data value. |
| Picked Cell Number | Integer | The current cell number being probed. This number is just used as a reference when probing. |
| Picked Cell Data | Integer | The current cell data value being probed. This number should be added to the Flip List if that patch needs to be flipped. |
| Flip List | Integer | The list of patches to have their normals flipped. Each patch is identified by its cell data value. |