Patch (3-D FFS)

3-D FFS > From boundary curves > Patch

Frequently required in modern design processes is the closing of gaps with appropriate surfaces while observing connection constraints.

These requirements can be fulfilled effortlessly by the creation of so-called patches. These are groups of surface parts which are created in such a way that they will have a pre-defined cycle of edges as boundaries.

You can use the Patch function to create individual freeform surfaces or a freeform surface set (with three or more edges as boundary). Adjoining surfaces are continued tangentially. The solution offered by HiCAD can also be remodelled individually, depending on particular technical demands or design requirements.

When you call the function the Patch dialogue window is displayed. Proceed as follows:

1. Identify the boundary of the patch. This can be the boundary curve of a solid or surface part, or the composite edge of a Sketch. It is important that the boundary forms a closed cycle!
2. Activate the Remodel checkbox if you want to individually remodel the patch offered by HiCAD.
3. Activate the Connect surfaces function if you want to connect the individual surfaces of a surface set topologically.
4. Exit the window with OK.
5. If you have activated the Remodel checkbox, another dialogue window is displayed. Here you can individually remodel the patch offered by HiCAD.

• One possibility to modify the form of the tangential patch is the entry of a form factor. By default, the form factor is set to 1.0, which means "no change".Only numbers being truly greater than 0.0 are allowed. Factors less than 1.0 cause a reduction, factors greater than 1.0 cause an increase of the concavity.
• Another procedure can be applied to patches with three or more than four edges. Here, a surface set is created that may also be modelled by moving the centre point at which the individual surfaces converge. An exception occurs only if you have specified exactly 4 edges, as in this case only one surface will be created.

Examples:

Tangential patch, boundary curve consisting of 3 edges, form factor 1

Tangential patch, boundary curve consisting of 3 patches, form factor 0.1

Coons patch, boundary curve with exactly 4 edges

Cylinder patch (original: top left) with various form factors

Freeform Surfaces from Boundary Curves (3-D FFS) • Overview of Functions (3-D FFS)