Select an editable patch. > Modify panel > Expand the editable patch in the stack display. > Edge sub-object level
Select an editable patch. > Modify panel > Selection rollout > Edge button
Select an editable patch. > Right-click the patch > Tools 1 (upper-left) quadrant of the quad menu > Sub-objects > Edge
An edge is the portion of a patch object between two adjacent vertices. When at the Editable Patch (Edge) level, you can select single and multiple segments and move, rotate, and scale them using standard methods. You can also hold down the SHIFT key and drag an edge to create a new patch. Holding down the SHIFT key during edge extrusion creates a new element.
Procedure
To unlock interior edges:
When you move an outer or boundary edge of a patch, the adjacent interior edges are normally "locked" so that they move in parallel with the boundary edge. This is often useful, because it provides a uniform transition across the patch. This default is known as Auto Interior.
At Patch level, you can change the default on a patch-by-patch basis by right-clicking a patch and choosing Manual Interior from the Tools 1 (upper-left) quadrant of the quad menu. Thereafter, when you move a boundary edge, interior edges are affected in a nonlinear way. The interior edges are no longer locked to the boundary edge.
Warning: If you return a patch to the default, changes caused by Manual Interior are lost.
Interface
Selection Rollout
Select Open Edges: Selects all edges that are used by only one patch. You can use this to troubleshoot a surface; open edges will be highlighted.
For information on the other controls in this rollout, see Editable Patch.
Soft Selection rollout
See Soft Selection Rollout for information on the Soft Selection rollout settings.
Geometry rollout
When Edit Patch is the active modifier and the Edge sub-object level is active, the Geometry rollout on the Modify panel has the options listed below:
Subdivision group
Subdivide: Subdivides selected edges and the associated patches. Select one or more edges, and then click Subdivide.
Propagate: When on, subdividing edges propagates the subdivision to neighboring patches. Propagating the subdivisions along all contiguous patches prevents patch cracks where you have attached patches together. Turning off the check box restricts subdivisions to just the one or two patches bordering each selected edge, and will create cracks in the edges between these patches and the surrounding ones.
Topology group
You can add Tri and Quad patches to any open edge of an object. On closed objects like a sphere, you can delete one or more existing patches to create open edges, and then add new patches.
The new patches adapt to the existing geometry. For example, when you add a patch to a curved edge, the new patch follows that curve and seamlessly extends it.
Add Tri: Adds a three-sided patch to each selected edge. Select one or more edges, then click Add Tri to add the patch or patches.
Original patch with edges selected (top) and three-sided patches added (bottom)
Add Quad: Adds a four-sided patch to each selected edge. Select one or more edges, and then click Add Quad to add the patch or patches.
Attach: Lets you attach an object to the currently selected patch object. Click the object you want to attach to the currently selected patch object.
For further details, see Attach.
Reorient: When on, reorients the attached patch so that each patch's creation local coordinate system is aligned with the creation local coordinate system of the selected patch.
Delete: Removes edges from the framework. Use this option with caution. Deleting an edge also deletes any patches that share the edge.
Break: Splits an edge. Use this if you need to split open an edge for general modeling operations. Select one or more edges and then click Break. After the break move the handles of adjacent vertices to create a gap in the patch.
Note: To move the handles away from each other, use Shift-Move.
Hide: Hides selected edges and the attached patches. You cannot hide an entire object this way; at least one patch always remains visible.
Unhide All: Restores any hidden sub-objects to visibility.
Weld group
Selected: Weld two edges that share vertices. Use this to eliminate gaps on a surface.
Extrude and Bevel group
Extrude: Click this button, and then drag any edge to extrude it interactively. Hold down the SHIFT key during this operation to create a new element.
When the mouse cursor is over a selected edge, it changes to an Extrude cursor.
With multiple edges selected, dragging on any one extrudes all selected edges equally.
You can drag other edges in turn to extrude them while the Extrude button is active. Click Extrude again or right-click to end the operation.
Extrusion: This spinner lets you extrude selected edges outward or inward, depending on whether the value is positive or negative. Hold down the SHIFT key during this operation to create a new element.
Normal: With Normal set to Group, extrusion takes place along the averaged normal of each contiguous group of edges. If you extrude multiples of such groups, each group moves along its own averaged normal. If Normal is set to Local (the default), extrusion takes place along each selected edge's normal.
Surface group
View Steps: Controls the grid resolution of the patch model surface as depicted in the viewports.
Show Interior Edges: Enables the display of the patch object's interior edges in wireframe views. When off, only the object's outline is visible. Turn on to simplify the display for faster feedback.
Miscellaneous group
Create Shape: Creates splines based on the selected edges. If no edges are selected then splines are created for all the patch edges. The software prompts you for a name, type in a name for the shape object and click OK.
Each patch edge forms an individual spline. Use this for creating a spline cage based on the patch edges. This is useful for spline modeling or Surface tools work.