How does the Weave option work in Extrude and Weave: creating over/under interlocking patterns like rope and basket weave?

Overview

The Weave option makes extruded shapes go alternately over and under where drive rails cross, creating rope, basket weave, or chain patterns. Without Weave, crossing rails simply merge into one shape.

Enabling Weave

Check the Weave under/over at crossings checkbox in the form. Two scaling options appear: Scale Shape or Add Base. Both use Z Under and Z Over percentage values. The official documentation shows 70% Z Under and 130% Z Over as a clearly visible weave.

Scale Shape vs. Add Base

Scale Shape: at crossings, the cross-section is scaled by the percentages. A Z Under of 50% makes the under-strand half its height, and a Z Over of 150% makes the over-strand one and a half times its height. This looks natural, but fine detail can be squashed or exaggerated at the overlaps. Best for rope, cable, and rounded profiles.

Add Base: the original cross-section height is kept and material is added underneath the shape according to the percentages. This usually gives a higher component but a consistent strand shape. Best for flat strips, lattice, and basket-weave patterns where scaling would look distorted. Use it when Scale Shape distorts your detail.

Weave With Vectors or Components

Weave works with either vector cross-section extrusions or Use a Component extrusions. With a component, a round rope or strand-shaped component gives the most convincing result. For the other options in the tool, see the entry on how Extrude and Weave works, and for fixing a weave that does not show, see the entry on why an Extrude and Weave result is wrong.

Which Strand Goes Over

The order of the weave is determined by the direction of the first drive rail vector you picked. To flip over and under, right-click the first selected rail, choose Reverse Rail, and Apply again. The strands swap.

Practical Rope Border Workflow

1. Draw two wave lines that cross each other along the desired border path
2. Select both as drive rails and click Use Selection
3. Draw a short straight line for the cross-section, enter Node Edit (N), insert a node at the midpoint, and drag it up to create a dome. This D-shaped open vector is the cross-section profile
4. Keep Smooth on (it is the default), enable Weave and Scale Shape, and try a Z Under around 70 to 80% and a Z Over around 120 to 130%. Treat these as starting values and adjust to taste
5. Apply. The strands weave over and under
6. Trim the result to the sign boundary with Clear Component Outside Selected Vectors

Basket Weave Pattern

1. Create a grid of horizontal lines and vertical lines
2. Select all as drive rails
3. Use a thin flat rectangular cross-section
4. Enable Weave and Add Base, and start with values near 80% Z Under and 120% Z Over
5. Result: flat strips alternating over and under in a basket pattern
6. Trim to the desired boundary (oval, sign shape, etc.) with Clear Component Outside Selected Vectors