Trelis 16.4 User Documentation

The collapse operation allows the user to collapse small angles using virtual geometry.

To collapse small angles

- On the Command Panel, click on
**Geometry**and then**Vertex**. - Click on the
**Modify**action button. - Select
**Collapse Angle**from the drop-down menu. - Enter in the appropriate settings for
**Vertex ID**. This can also be done using the**Pick Widget**function. - Enter in the appropriate setting on this menu for
**c1**and**c2**. - Click
**Apply**.

Collapse Angle at Vertex <id> Curve <id1> [Arc_length1 <length>] Curve <id2> [Arc_length2 <length> | Same_size | Perpendicular | Tangent] [Composite_vertex <angle>] [Preview]

The collapse angle command is used to eliminate small angles at vertices, where curves meet at a tangential point. The command will split each curve at a specified distance (?1 and ?2 ) as shown in Figure 1, and create two new vertices along those curves. The remaining small angle will be composited into its neighboring surface using virtual geometry. The options of the command allow you to specify where to split each curve. You must input a distance for the first curve ( ?1), but the second location can be determined based on the length and direction of the first curve.

The **arclength** option will split each curve at a specified
distance ?1 and ?2,
(See Figure 1) measured from the vertex. You must input at least one **arclength**
for each of the options listed below.

The **same_size** option will split curve 2 so that the
two resulting curves, ?1 and ?2,
are the same length as shown in Figure 2.

The **perpendicular** option will split curve 2 so it is
perpendicular to the split location on curve 1, as shown in Figure 3.

The **tangent** option will split curve 2 where a line
tangent to curve 1 at the split location intersects curve 2, as shown
in Figure 4.

The **composite_vertex** option automatically composites
resulting surfaces if there are only two curves left at the vertex, and
the angle is less than a specified tolerance.

The **preview** option will preview composited surface
before applying changes.