## Name

nmg_collapse — Simplifies an existing nmg_shape by a process of edge decimation.

## Synopsis

`nmg_collapse` {`old_nmg_shape new_nmg_shape maximum_error_dist`} [`minimum_angle`]

## DESCRIPTION

Simplifies an existing nmg_shape by a process of edge decimation. Each edge in the old_nmg_shape is considered; if it can be deleted without creating an error greater than the specified maximum_error_dist, then that edge is deleted. If a minimum_angle is specified (degrees), then the edge will not be deleted if it would create a triangle with an angle less than minimum_angle. The resulting shape is saved in new_nmg_shape. The old_nmg_shape must have been triangulated previous to using the nmg_collapse command. The resulting shape consists of all triangular faces.

## EXAMPLES

The example shows the use of the nmg_collapse command to simplify an existing nmg shape by decimating its edges. The new nmg shape will be within a maximum error distribution and will not have any triangles with angles less than a given minimum.

Example 1. Create a new nmg shape by decimating the edges of an existing nmg shape.

`mged>``nmg_collapse nmg_old nmg_new 1.0 10.0`

Decimates edges in nmg_old to produce an NMG with an error no greater than 1.0 units. The process will not create any triangles with an angle less than 10°. The new NMG shape will be named nmg_new.

## BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to <devs@brlcad.org>, or via the "cadbug.sh" script.