NMG_COLLAPSE nged BRL-CAD BRL-CAD User Commands
nmg_collapse Simplifies an existing nmg_shape by a process of edge decimation.
`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.

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.

## AUTHOR

BRL-CAD Team

## BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org