Creating Swept Surfaces Using a Linear Profile

This task shows how to create swept surfaces that use an implicit linear profile.

The following subtypes are available:

• Two limits

• Limit and middle

• With reference surface

• With reference curve

• With tangency surface

• With draft direction

• With two tangency surfaces

Open the Sweep1.CATPart document.

Two limits:

1. Click Sweep .

   The Swept Surface Definition dialog box appears.

2. Click the Line profile icon and select Two Limits from the Subtype drop-down list.

3. Select two guide curves.

4. You can enter one or two length values to define the width of the swept surface.

5. If needed, select a Spine to specify a spine different from the first guide curve.
   If no spine is selected, the guide curve is implicitly used as the spine.
   If a plane normal to the spine intersects one of the guiding curves at more than one points, the application chooses the closest point to the spine point.

6. Click OK to create the swept surface.

   The surface (identified as Sweep.xxx) is added to the specification tree.

Limit and middle:

1. Click Sweep .

   The Swept Surface Definition dialog box appears.

2. Click the Line profile icon and select Limit and Middle from the Subtype drop-down list.

3. Select two guide curves.

4. Check Second curve as middle curve to use the second guide curve as the middle curve.

   	Checking Second curve as middle curve automatically selects this mode.

5. If needed, select a Spine to specify a spine different from the first guide curve.
   If no spine is selected, the guide curve is implicitly used as the spine.
   If the plane normal to the spine intersects one of the guiding curves at different points, it is advised to use the closest point to the spine point for coupling.

6. Click OK to create the swept surface.

   The surface (identified as Sweep.xxx) is added to the specification tree.

With reference surface:

1. Click Sweep .

   The Swept Surface Definition dialog box appears.

2. Click the Line profile icon and select With reference surface from the Subtype drop-down list.

3. Select a guide curve, a reference surface and key in an angle value.

   The guiding curve must lie completely on this reference surface, except if the latter is a plane.

4. You can enter one or two length values to define the width of the swept surface.

   	The angular definition defined by the law (if selected) applies to the projection of the normal to the reference element in the sweeping plane normal to the spine.

5. If needed, select a Spine to specify a spine different from the first guide curve.
   If no spine is selected, the guide curve is implicitly used as the spine.
   If the plane normal to the spine intersects one of the guiding curves at different points, it is advised to use the closest point to the spine point for coupling.

6. Click OK to create the swept surface.

   The surface (identified as Sweep.xxx) is added to the specification tree.

With reference curve:

1. Click Sweep .

   The Swept Surface Definition dialog box appears.

2. Click the Line profile icon and select With reference curve from the Subtype drop-down list.

3. Select a guide curve, a reference curve, and key in an angle value.

4. You can enter one or two length values to define the width of the swept surface.

5. If needed, select a Spine to specify a spine different from the first guide curve.
   If no spine is selected, the guide curve is implicitly used as the spine.
   If the plane normal to the spine intersects one of the guiding curves at different points, it is advised to use the closest point to the spine point for coupling.

6. Click OK to create the swept surface.

   The surface (identified as Sweep.xxx) is added to the specification tree.

With tangency surface:

1. Click Sweep .

   The Swept Surface Definition dialog box appears.

2. Click the Line profile icon and select With tangency surface from the Subtype drop-down list.

3. Select a guide curve, and a reference surface to which the sweep is to be tangent.

4. Depending on the geometry, there may be one or two solutions from which to choose, either by clicking on the solution displayed in red (inactive), using the Previous or Next buttons or entering a solution number in the Solution(s) field.

5. You can check the Trim with tangency surface to perform a trim between the swept surface and the tangency surface. The part of the tangency surface that is kept is chosen so that the final result is tangent.

   Two solutions
   Choosing solution 2		Choosing solution 2 with Trim option

6. If needed, select a Spine to specify a spine different from the first guide curve.
   If no spine is selected, the guide curve is implicitly used as the spine.
   If the plane normal to the spine intersects one of the guiding curves at different points, it is advised to use the closest point to the spine point for coupling.

7. Click OK to create the swept surface.

   The surface (identified as Sweep.xxx) is added to the specification tree.

With draft direction:

1. Click Sweep .

   The Swept Surface Definition dialog box appears.

2. Click the Line profile icon and select With draft direction from the Subtype drop-down list.

3. Select a guide curve and a draft direction (a line, a plane or components).

4. Select the draft computation mode:

   Square: equivalent to implicit linear profile swept surface with reference surface, using a plane normal to the draft direction as reference surface, and the projection of the guide curve onto this plane as spine. Cone: envelop of cones defined along a given curve. In order to have swept start and end planes similar as the square mode, the guide curve needs to be extrapolated and the resulting surface split as explained in the following figure. Choose the angular definition: Wholly defined: the angular value varies during the whole sweeping operation G1-Constant: a different draft value for every G1 section can be set; in this case, a relimiting plane is requested when defining lengths Location values: on given points on the curve, angular values can be defined. The Location values tab is only available for a square computation mode and will work only on G1 curves.

5. Choose the length types:

   From curve: the swept surface starts from the curve Standard: the length is computed in sweeping planes (defining 0 is similar as choosing From curve) From/Up to: the length is computed by intersecting a plane or a surface; a point can be selected: a plane parallel to the draft plane would be computed From extremum: the lengths are defined along the draft direction from an extremum plane; L1 corresponds to the maximum plane in the draft direction, L2 corresponds to the minimum plane in the draft direction Along surface: the length is used as the distance of an euclidean parallel curve to relimit the swept surface

   The start (or end) section of the swept surface (in yellow) does not coincide with the expected relimiting plane (in green). As a consequence, the blue portion needed is missing. Here are the steps performed to create the swept surface. As an information purpose, we put all the elements explaining the steps above in Geometrical Set.2, so that you understand how the sweep surface is created. The guide curve is extrapolated in curvature (pink curve) The result is split by the green plane to obtain the green end section.

6. Click OK to create the swept surface.

   The surface (identified as Sweep.xxx) is added to the specification tree.
   In the above example, we selected the following values: Curve.1 as guide curve Plane.1 as draft direction Square as computation mode 20deg as Wholly constant angle Standard Length type 50mm as Length 1		In the above example, we selected the following values: Curve.1 as guide curve Plane.1 as draft direction Square as computation mode 35deg as Wholly constant angle From / Up To Point 1 as Relimiting element 1 20mm as Length 2
   In the following example, we selected the following values: Curve.1 as guide curve Plane.1 as draft direction Cone as computation mode 20deg as Wholly constant angle From Extremum type 50mm as Length 1		In the following example, we selected the following values: Curve.1 as guide curve Plane.1 as draft direction Square as computation mode 20deg as Wholly constant angle Along surface type 30mm as Length 1

Be careful when using a draft direction and a planar guide that is not continuous in tangency: it may lead to an invalid topology with surfaces that are not joined, if the draft angle is not constant or if the draft direction is not normal to the guide plane. We advise you to use a relimiting plane in order to cut surfaces and obtain a valid topology.

With two tangency surfaces:

1. Click Sweep .

   The Swept Surface Definition dialog box appears.

2. Click the Line profile icon and select With two tangency surfaces from the Subtype drop-down list.

3. Select a spine, and two tangency surfaces.

4. You can check the Trim with tangency surface to perform a trim between the swept surface and the tangency surface. The part of the tangency surface that is kept is chosen so that the final result is tangent.

   Swept surface without trim		Trim with both surfaces
   Trim with first tangency surface		Trim with second tangency surface

5. If needed, select a Spine to specify a spine different from the first guide curve.
   If no spine is selected, the guide curve is implicitly used as the spine.
   If the plane normal to the spine intersects one of the guiding curves at different points, it is advised to use the closest point to the spine point for coupling.

6. Click OK to create the swept surface.

   The surface (identified as Sweep.xxx) is added to the specification tree.

Previewing The Angular Value

This option is only available with the With reference surface, With reference curve and With draft direction subtypes.

Optional Elements