Selecting Polygon Mesh Components

This section describes some special commands that can be used only to select points, edges, and polygons on polygon mesh objects.

Select > Grow Selection adds to the selection those components that are both adjacent to and of the same type as the current selection.

• The commands on the Select > Select Adjacent submenu select the components of the specified type that are adjacent to the current selection.

Select > Select Edge Loop selects connected edges passing through vertices where four edges meet.

• The commands on the Select > Select n-Sided Polygons submenu allow you to select polygons based on their number of sides: triangles, quads, and others.

• You can use polynode bisectors to help select a point that overlaps others.

For a description of the standard methods that can be used to select any type of component, see Selecting Components [Scene Elements].

Growing the Selection

When polygon mesh components are selected, you can add adjacent components of the same type to the selection by growing it.

To grow the selection

1. Select some polygons, edges or points on a polygon mesh object.

2. Choose Select > Grow Selection from the Select panel or press Shift+=.

- If points are selected, then all points that are share a polygon are added to the selection.

 

- If edges are selected, then all edges that share a point are added to the selection.

 

- If polygons are selected, then all polygons that share a point are added to the selection.

 

Shrinking the Selection

Shrinking deselects components that are adjacent to unselected components or that are on boundaries.

To shrink the selection

• With points, polygons, or edges on a polygon mesh selected, choose Select > Shrink Selection.

Selecting Adjacent Components

When polygon mesh components are selected, you can select the components of a specific type that are adjacent to the current selection.

To select adjacent components

1. Select some polygons, edges, points, or clusters on a polygon mesh object.

2. Choose one of the items on the Select > Select Adjacent submenu on the Select panel: Points, Edges, or Polygons.

- If you choose a different type of component than the current selection, all components of that type that share or are shared by the current selection become selected. For example, if polygons are selected and you choose Points, then all points that are shared by the polygons become selected.

- If points are selected and you choose Points, then all points that share an edge with the selected ones become selected.

 

- If edges are selected and you choose Edges, then all edges that share a point with the selected ones become selected.

 

- If polygons are selected and you choose Polygons, then all polygons that share an edge with the selected ones become selected.

 

Selecting Edge Loops

The Select menu has commands for selecting edge loops and parallel edge loops on polygon meshes.

 

As an alternative to these commands, you can use the range and loop selection features of the component selection tools. See Selecting Ranges and Loops of Components [Scene Elements].

Selecting Edge Loops

Edge loops are lines of connected edges. Edge loops are useful in polygon modeling because they define the “flow lines” or “contour lines” of your object.

There are two commands for selecting edge loops on the Select menu:

Select Edge Loop (no corners)

Select Edge Loop (around corners)

For interior edges, these commands do the same thing. At a vertex where four edges meet (+ junctions), the edge loop continues along the middle of the three other edges. The edge loop stops at vertices where two, three, five or more edges meet, or where it meets itself on the other side of the object.

 

Selecting interior edge loops: Loops continue where 4 edges meet, but stop where there are more or fewer edges (A) and where the loop meets itself on the other side (B).

For boundary edges, the commands behave differently:

Select Edge Loop (no corners) extends the selection along the top of T and Y junctions.

Select Edge Loop (around corners) selects the entire connected boundary.

 

Selecting boundary edge loops: No Corners (A) passes through T and Y junctions but stops anywhere else, while Around Corners (B) selects the entire boundary.

To select edge loops

1. Choose Select > Select Edge Loop (no corners) or Select > Select Edge Loop (around corners).

2. Pick a polygon mesh object. The object becomes active for edge loop selection.

3. Pick one or more edge loops as desired:

- Click or middle-click on an edge to select the corresponding edge loop.

- Shift+click on an edge to add the corresponding loop to the selection.

- Ctrl+click on an edge to toggle the corresponding loop.

- Ctrl+Shift+click on an edge to remove the corresponding loop from the selection.

- Activate additional polygon mesh objects for edge loop selection by picking them with the left or middle mouse button.

4. When you have finished, right-click or press Esc to terminate the picking session.

Selecting Parallel Edge Loops

Parallel edge loops consist of the non-adjacent edges that are opposite each other along a strip of quads.

 

In some cases, Select Parallel Edge Loop also selects edges on non-quads if they are parallel enough.

To select parallel edge loops

Parallel edge loops are strips of unconnected edges along a row of quadrilateral polygons.

1. Choose Select > Select Parallel Edge Loop.

2. Pick a polygon mesh object. The object becomes active for edge loop selection.

3. Pick one or more edge loops as desired:

- Click or middle-click on an edge to select the corresponding edge loop.

- Shift+click on an edge to add the corresponding loop to the selection.

- Ctrl+click on an edge to toggle the corresponding loop.

- Ctrl+Shift+click on an edge to remove the corresponding loop from the selection.

- Activate additional polygon mesh objects for edge loop selection by picking them with the left or middle mouse button.

4. When you have finished, right-click or press Esc to terminate the picking session.

Selecting Triangles, Quads, or Other Polygons

You can quickly select polygons based on their number of sides: triangles, quads, or other polygons.

To select triangles, quads, or other polygons

1. Select one or more polygon mesh objects.

2. Choose one of the following commands from the Select > Select n-Sided Polygons submenu:

- Triangles: Selects all three-sided polygons on the active objects.

- Quads: Selects all four-sided polygons (quadrilaterals) on the active objects.

- Five Sides or More: Selects all the non-triangle, non-quad polygons.

 

You can also use the Triangle, Quad, and N-gon filters to select these types of polygons interactively using one of the selection tools. These filters are available on the Filters menu (the triangle above the Selection boxes on the Select panel).

Selecting Points That Overlap Others

Polynode bisectors can be useful when selecting or moving points that overlap others on a polygon mesh object.

To select or move a point that overlaps others

1. Open the Camera Visibility property editor of a 3D view, for example, by pressing Shift+S.

2. On the Components tab, set Show Polynode Bisectors to Show While Drawing Points.

With this option, bisectors are displayed as small purple lines at the corners of polygons whenever points are visible.

3. Activate point selection (for example, press T for Rectangle Point Selection) or the Tweak Component tool (press M).

4. Click on a bisector to affect the corresponding point.



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