3D Graphics Programming with QuickDraw 3D 1.5.4

Trim Loops

Labels

ASCII: TrimLoop
Binary: trml ( = 0x74726D6C )

Data Format

None.

Data Size

Description

A trim loop object is used to bind two-dimensional curves to a NURB patch for the purpose of trimming that patch. As of this release, only 2D NURB curves may be used for trimming.

Trimming curves are attached to a NURB patch by placing them in a container the root object of which is a trim loop object and placing that container in a further container together with the relevant NURB patch.

The two-dimensional curves governed by a trim loop object must form a sequence such that the last control point of the i th curve is also the first control point of the i +1st curve, and the last control point of the last curve is also the first control point of the first curve.

Default Surface Parameterization

None.

Parent Hierarchy

Data.

Parent Objects

NURB patch (always).

Child Objects

2D NURB curves (required). A trim loop object may have several child objects.

Example



 
Container (

    NURBPatch (...)

    Container (

    TrimLoop ( )

        NURBCurve2D (...)

        .

        .

        .

        NURBCurve2D (...)

    )

Default Size

None.