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Manual - Blender 2.4

[edit] Edge Tools

[edit] Introduction

Loop/Cut Menu.

A key issue in modeling is the necessity to add vertices in certain zones of the mesh, and this is often regarded as splitting, or adding, edges in a given region.

Loops often play an important role in this process. For a brief introduction to loops, please refer to Edge and Face Loops.

Many edge tools are grouped in a menu which is linked to K hotkey (Loop/Cut Menu), but each individual tool has its own hotkey as well.

Edge Specials menu.

Edge Tools for selection and manipulation are grouped in a menu which is linked to CtrlE hotkey (Edge Specials menu).

Edge Slide, for example, slides the vertices in the loop along the edges. If you select a loop on an egg-shaped object, for example, sliding the vertices will move them, not left/right or up/down, but instead proportionally move them as if they were sliding along the edge using the edge as a guide. More information on selecting loops is found below.

[edit] Edge Selection

[edit] Description

Select modes.

In Edit mode, there are a few ways to select edges: implicitly, explicitly, looping or by region selection. Implicit means you describe a more complex element using less complex elements. For example, to describe an edge you need to specify two vertices and to describe a face you need to specify three or more vertices or three or more edges.

Region selection is a tool that allows selection of edges and faces based on an intersection with a rectangular, circular or lasso 2D region.

Explicit Edge Selection

To select an edge use edge select mode and RMB click on an edge. To select additional edges use ⇧ ShiftRMB .

Implicit Edge selection.

Implicit Edge Selection

The other way to select an edge is to select two vertices that bound the edge of interest. You are implying which edge by selecting its bounding vertices. To select an edge implicitly use vertex select mode in combination with RMB and/or ⇧ ShiftRMB .

In (Implicit Edge selection), the cube on the left shows an edge selected using vertices. The cube on the right is what shows when you switch to edge select mode.

[edit] Options

If you are in solid, shaded, or textured viewport shading mode (not bounding box or wireframe), you will have a fourth button that looks like a cube. When enabled, this limits your ability to select based on visible edges (as if the object was solid), and prevents you from accidentally selecting, moving, deleting or otherwise working on backside or hidden edges.

[edit] Edge Loop Selection

[edit] Description

Holding Alt while selecting an edge selects a loop of edges that are connected in a line end to end, passing through the edge under the mouse pointer. Holding Alt⇧ Shift while clicking adds to the current selection. Edge loops can also be selected based on an existing edge selection, using the Edge Specials » Edge Loop Select menu option (CtrlE).

[edit] Examples

Longitudinal and latitudinal edge loops.

The left sphere shows an edge that was selected longitudinally. Notice how the loop is open. This is because the algorithm hit the vertices at the poles and terminated because the edge at the pole connects to more than 3 other edges. However, the right sphere shows an edge that was selected latitudinally and has formed a closed loop. This is because the algorithm hit the first edge that it started with.

[edit] Technical Details

The algorithm for selection is as follows:

• First check to see if the selected element connects to only 3 other edges.
• If the edge in question has already been added to the list, the selection ends.
• Of the 3 edges that connect to the current edge, the ones that share a face with the current edge are eliminated and the remaining edge is added to the list and is made the current edge.

[edit] Edge Ring Selection

[edit] Description

In edge select mode, holding CtrlAlt while selecting an edge selects a sequence of edges that are not connected, but on opposite sides to each other continuing along a face loop. Using the same command in vertex select mode will select such a face loop implicitly.

[edit] Examples

A selected edge loop, and a selected edge ring.

In (A selected edge loop, and a selected edge ring), the same edge was clicked on but two different “groups of edges” were selected, based on the different commands. One is based on edges during computation and the other is based on faces.

[edit] Technical Details

Edge ring selection is based on the same algorithm as in Face Loop Selection, though the end results differ as only some edges are selected.

[edit] Rotate Edge CW / Rotate Edge CCW

[edit] Description

Rotating an edge clockwise or counter-clockwise spins an edge between two faces around their vertices. This is very useful for restructuring a mesh’s topology. The tool can operate on one explicitly selected edge, or on two selected vertices or two selected faces that implicitly select an edge between them.

[edit] Examples

Selected edge rotated CW and CCW.

Be aware that sometimes, as shown in (Selected edge rotated CW and CCW), indicated with a “T”, that you could produce what appears to be “T” junctions/nodes by using this tool. However, Blender has created additional edges that prevent cracks in the mesh. You can test this by selecting the vertex at the “T” and moving it around while noting that there are two edges now instead of one long edge.

Adjacent selected faces.

To rotate an edge based on faces you must select two faces, (Adjacent selected faces), otherwise Blender notifies you with an error message, “ERROR: Select one edge or two adjacent faces”. Using either Rotate Edge CW or Rotate Edge CCW will produce exactly the same results as if you had selected the common edge shown in (Selected edge rotated CW and CCW.).

[edit] Edge Slide

[edit] Description

Edge Slide slides one or more edges along faces adjacent to the selected edge(s) with a few restrictions involving the selection of edges.

[edit] Options

• LMB confirms the tool, and RMB or Esc cancels.
• This tool has both a Percentage and Proportional mode, which is displayed in the 3D View header. These modes behave the same as with the Loop Subdivide tool, including all keys for controlling precision edge movement.

[edit] Examples

Simple edge slide.

(Simple edge slide) is an example of sliding an edge along an extruded box. The selected edge is labeled “E” and the adjacent faces to that edge are “F1” and “F2”. In “Edge moving”, the edge is being slid along the edge drawn in green. “Moved” shows the results.

[edit] Limitations & Workarounds

Loop crosses.

Single edges.

Order loop.

There are restrictions on the type of edge selections that can be operated upon. Invalid selections are:

“Loop crosses itself”

This means that the tool could not find any suitable faces that were adjacent to the selected edge(s). (Loop crosses) is an example that shows this by selecting two edges that share the same face. A face cannot be adjacent to itself.

“Was not a single edge loop”

Most likely you have selected edges that don’t share the same edge loop. (Single edges) is an example where the selected edges are not in the same edge loop, which means they don’t have a common edge. You can minimize this error by always selecting edges end to end or in a “Chain”.

“Could not order loop”

This means the tool could not find an edge loop based on the selected edge(s). (Order loop) is an example where a single edge was selected in a 2D Plane object. An edge loop can not be found because there is only one face. Remember, edge loops are loops that span two or more faces.

A general rule of thumb is that if multiple edges are selected they should be connected end to end such that they form a continuous chain. This is literally a general rule because you can still select edges in a chain that are invalid because some of the edges in the chain are in different edge loops. (Loop crosses) is just such an example where the selected edges form a chain but they are not in the same edge loop.

If you select multiple edges just make sure they are connected. This will decrease the possibility of getting looping errors.

[edit] Bevel

[edit] Description

With bevel and without bevel.

A bevel is something that smooths out a sharp edge or corner. True world edges are very seldom exactly sharp. Not even a knife blade edge can be considered perfectly sharp. Most edges are intentionally beveled for mechanical and practical reasons.

Bevels are also useful for giving realism to non-organic models. In the real world, the blunt edges on objects catch the light and change the shading around the edges. This gives a solid, realistic look, as opposed to un-beveled objects looking false.

[edit] Options

Recursion level.

Recursion

The number of recursions in the bevel can be defined in an additional popup number field. The greater the number of recursions, the smoother the bevel.

If it is one, then each face is reduced in size and each edge becomes a single new face. Tri and quad faces are created as necessary at the corresponding vertices. If the Recursion number is greater than one, then the bevel procedure is applied that number of times. Hence, for a Recursion of 2 each edge is transformed into 4 edges, three new faces appear at the edge while smoothing the original edge. In general the number of new edges is 2 elevated to the Recursion power.

Width

Bevel window header.

You can change the bevel width by moving the mouse towards and away from the object. As usual, the scaling can be controlled to a finer degree by either holding Ctrl, to scale in 0.1 steps, or by holding ⇧ Shift to scale in 0.001 steps. LMB finalizes the operation, RMB or Esc aborts the action.

Alternatively, you can manually enter a scaling value by pressing Space. A popup dialog appears, asking you to type in the beveling scale factor labeled as Width. The scale is limited to a range from 0.0 to 10.0 and upon hitting OK the bevel action is completed.

[edit] Hints

Remember that in each recursion, for each new edge two new vertices are created, with additional vertices created at the intersection between edges. This means your vertex count can quickly become enormous if you bevel with a high recursion!

[edit] Bevel Selected Edges

With the W » Bevel command, all edges of a given mesh are beveled. To bevel only selected edges, use the “Bevel Center” script instead.

As already pointed, you are encouraged to use the Bevel modifier and its bevel weight option to control which edges are beveled, and to which extent.

[edit] Examples

(Beveling a cube) is an example of beveling a cube with a Recursion of 2. Once the Recursion number is set each face of the mesh receives a yellow highlight. The cube labeled “Bevelling” is the tool in action.

The final result can be seen in the cube labeled “Beveled” or “Shaded”.

Beveling a cube.

Manual