Surfaces > Rolled Edge > Fillet Flange
Creates a fillet and a flange to refine the edges of a surface model.
The Fillet Flange tool provides you with automatic functionality that creates a finish on the edges of a surface model. By using one or more of the following: edge, curve-on-surface, boundary edge, or iso-parametric line, the tool creates a temporary, imagined wall used for construction only on the selected geometry. This wall can be based on a pull direction vector or on the surface normal at the selected geometry. Using this wall and the input geometry, the tool creates a surface fillet. Additionally, the Fillet-flange tool creates a linear extension called a Flange on the fillet. This extension can be defined by a sweep angle or a vector plus a draft angle.
Fillet Flange Control options
Wall
Type
Set to either Draft or Normal. In Draft mode, the wall is defined by a pull direction vector plus a draft angle. Wall (for both Draft and Normal) defines the configuration of the fillet tangent. For Draft, a pull direction vector must be picked. The vector is highlighted in light blue (the same color is used for showing the wall). Normal builds a normal-based wall.
Angle/Draft Angle
The angle to the input surface normal at each point of the input curves, or the Draft Angle if Draft has been selected as the Type
Flip
Enables you to put the wall on top of, or underneath the surfaces, so the fillets and flanges are built on the other side of the surfaces. You can also click the blue arrow manipulator on the model to flip the side.
Draft Vector Options
These options only apply when Wall Type is set to Draft.
X,Y, Z
Select one of these to specify a pull direction along that axis.
View
Select this option to specify a pull direction normal to the current view. The vector is not drawn in the view windows.
If the current view is changed, click Refresh View Vector to update the vector.
Picked
Selecting this option lets you specify the name of an existing vector in the Picked Vector field, or pick the vector in the view. This vector defines the pull direction.
Refresh View Vector
This button only appears if View is selected. Click it to update the vector if the view has been modified.
Retain Vector
Click this button to create a vector construction object in the view windows. Unless you do this, the vector direction you specified is used by the tool, but you will not see and be able to re-use the vector.
Fillet
Continuity
Choose either G1 Tangent or G2 Curvature continuous to the base surfaces.
Flip
Enables you to flip the fillet on the other side of the wall. This option is grayed out if at least one of the input curves is an edge, and thus, it’s possible to build a fillet only on one side of the wall.
Specify
Choose whether you want to specify the Center radius, Tangent offset, or Both.
If Specify is set to Center radius or Tangent offset, and you also set the Form factor, the third parameter (either Tangent offset or Center radius) varies along the fillet. Both lets you specify both the Tangent offset and Center radius of the fillet, but not the Form factor. The form factor is calculated automatically from these two values and varies along the fillet.
Center radius
Radius at the center of the fillet (as measured along the arc length).
Tangent offset
Radius of a sphere that is tangent to the input surface(s) at the contact line, and is also tangent to the wall. (The contact line is the line along which the new fillet surface touches the input surfaces.)
Visually, it corresponds to the radius of the blue arc manipulator visible on the model (when Variable is set to Radius).
Form factor
This parameter lets you adjust the shape of the fillet. It specifies the ratio between the lengths of the innermost and outermost CV arms of the hull in the V direction of the fillet. Values range from 0.1 to 2.0. The smaller the value, the sharper the bend in the fillet.
In the example below, we specify the tangent offset to be 60.0 and let the center radius vary.
Form factor set to 0.1, creating a small center radius and a sharper bend in the fillet.
Form factor set to 2.0, creating a large center radius and a more circular fillet shape.
The Specify, Tangent offset and Center radius options are only available if a single radius manipulator is used. If the fillet has more than one manipulator (which in fact control the tangent offset), then the Form factor directly controls the center radius, hence the shape of the fillet at its peak.
Flange
Type
Set to either Sweep Angle or Parting Line. Sweep Angle defines where along the fillet the flange will be tangent to the fillet. Parting Line uses a vector and draft angle that determines the direction of the flange.
If you select Parting Line, you must pick a vector or specify it through the Parting Line Vector Options, unless Wall Type is set to Draft, in which case the draft vector (shown in blue) will be used as the parting line pull direction by default. To specify a different vector for the parting line, Shift-pick it, or use the Parting Line Vector Options.
Sweep Angle or Draft Angle
Provides a slider to control the angle. The default is 90 degrees for Sweep, and 0 for Draft angle. Either angle can be variable.
Create Flange
Determines whether or not a flange will be built off the edge of the fillet. Note that the fillet will be trimmed according to the Sweep Angle or Parting Line settings, even if Create Flange is off.
Length
Determines the length of the flange that will be built, if Create Flange is on. Length can be variable.
Explicit Control
Gives you controls of the surface degree and maximum number of spans in the fillet and flange surfaces.
Explicit Control Options
(Length) U Degree
The degree of the fillet and flange surface in the U direction (that is along the edge). Enter a whole number from 2 to 9. This option is only available when Explicit Control is checked.
(Section) V Degree
The degree of the fillet surface in the V direction. Enter a whole number from 3 to 6. This option is only available when Explicit Control is checked.
The degree of the flange surface in the V direction is always 1.
Max. Spans
If Surface Type is set to Multiple surfaces, this value specifies the maximum number of spans for each fillet and flange surface. If Surface Type is set to Single surface, it specifies the maximum number of spans for each piece of the original surfaces.
This option is only available when Explicit Control is checked, and Bézier Surfaces is not checked.
Parting Line Vector Options
These options only apply when Flange Type is set to Parting Line.
X,Y, Z
Select one of these to specify a pull direction along that axis.
View
Select this option to specify a pull direction normal to the current view. The vector is not drawn in the view windows.
If the current view is changed, click Refresh View Vector to update the vector.
Picked
Selecting this option lets you specify the name of an existing vector in the Picked Vector field, or pick the vector in the view. This vector defines the pull direction.
Refresh View Vector
This button only appears if View is selected. Click it to update the vector if the view has been modified.
Retain Vector
Click this button to create a vector construction object in the view windows. Unless you do this, the vector direction you specified is used by the tool, but you will not see and be able to re-use the vector.
Create Vector
Click this button to create a draft pull direction vector.
Click in the view to place the start of the axis, or type the position and press 
. Use the vector manipulator to position the vector and click Accept.
Fillet Flange Range
Modify Range
When this option is selected, Start and End sliders appear in the control window, and arrow manipulators appear on the selected fillet/flange. Drag these arrows to modify the extent of the fillet/flange across the input surfaces.
Start/End
Use these sliders to modify the extent of the tangent line that is used to build the fillet. Start and End values of 0.0 and 1.0 respectively, define the original extent.
Surface Structure
Surface Type
Single surface – A single fillet surface is built.
Multiple surfaces – The fillet is split at curve boundaries, which also include surface boundaries, since a curve cannot span more than one surface.
Curves-on-surface created at the edges of the fillets (visible when Auto Trim is off) are segmented to correspond to the multiple fillet surfaces.
Bézier Surfaces
This option only appears if Surface Type is set to Multiple surfaces. If it is checked on, each surface will be a Bézier patch.
Bézier patches have a single span, and their maximum degree in the U direction is set through the Explicit Control section. The default is degree 5.
Short Edge Tolerance
In the case of cross-knot insertion, the system will not allow spans of a linear distance less than the Short Edge Tolerance.
Control Options
Note that only one of the three parameters can be variable. For example, it is not possible to create a variable radius fillet with a variable length flange.
Variable
Gives you the ability to interactively modify the Flange Length, Flange Angle, or Radius.
Auto Update
Choose between updating changes by selecting the Updatebutton, or automatically updating changes.
If Auto Update is set off, use the spacebar to press the Update button.
Inter Continuity Check
Checking on this option displays continuity locators between the output surfaces, indicating whether or not they are tangent continuous. Green T locators indicate that the surfaces are tangent continuous while red/yellow T locators indicate they are not.
The Continuity Angle from Preferences > Construction Options is used when testing for tangent continuity, and a shared boundary is only checked if it doesn't present any gap larger than the Topology Distance tolerance (also found in Construction Options).
Only natural (non-trimmed) edges are checked.
Show Wall
Displays the imaginary wall that is used in the calculation of the fillet.
Auto Trim
Choose whether to have the surfaces automatically trimmed, or just to place the curves-on-surface.
Continuity Check
Choose whether to get visual feedback about continuity (set in the Fillet section). Green indicates success; yellow indicates that the continuity condition has not been met.
Chain Select
If this box is checked, selecting a surface curve also selects all other surface curves that are tangent continuous with it.
Create Metadata
Specifies whether or not the Fillet Flange tool creates history metadata.Note: The Create Metadata option is available only with Autodesk Alias 2019.2 or later.
To extend a Fillet flange
You can specify whether a fillet surface needs to be extended along the rail to reach the boundary of the input surface at each end of the rail. To toggle an extension at a rail end, click the green arrow appearing at that end. The arrow is shown in light green when extension is on. If the rail is closed, that is, its endpoints coincide, extension is not useful, and, therefore, the arrows are not shown.
To control the variable parameter in Fillet flange
The variable parameter (Radius, Flange angle, or Flange length — as specified by Variable in the control window) is controlled using a set of manipulators in the modeling window. Only one of the parameters can be varied: the other two are held constant.
Despite its name, Radius controls the Tangent offset, not the Center radius.
Each manipulator consists of two handles — the rail slider and the value handle — only one of which can be active at a given time. The active handle is shown in light blue. The rail slider, a "ball" sliding along the rail, indicates the position on the rail where the value applies. The value handle, an approximate cross section of the future surface, controls the value of the parameter at this point.
The value of the active handle is shown on the prompt line.
For all of the following operations, use the 
, unless stated otherwise.
To activate a handle, click it.
To de-activate the currently active handle and switch back to the picking mode, click anywhere on the screen (without dragging the mouse).
To add a new manipulator, 
-click the desired point on the rail.
To move a manipulator, drag the slider using the . Alternatively, activate the slider and type in the position (in the range from 0 to 1) along the rail.
To adjust the parameter value, click and drag the value handle. Once the handle is active, the mouse can be dragged anywhere on the screen. Alternatively, activate the handle and type in the value in current units.
To delete a manipulator, -right click it.
If a single manipulator is used, the parameter is constant, and its value can also be adjusted in the control box. As soon as another manipulator is added, the value in the control box is grayed out.