# Synopsis

PDX_MSGT gdb_PolyShellEvalTopology(long option, int opt_level, MDA_PTR gdx_ps_ptr)

# Purpose

Evaluate topological validity of GDX PolyShell Entity

# Description

Evaluate GDX PolyShell Entity for topological validity defined by loop orientation, stitching, overused edges, geometry closure, topology closure, segment status. Evaluation outputs: mass properties area, volume, centroid closure (geometry) GDX PolyShell Entity bounds model space segment properties manifold, shared, duplicate counts SOLID GDX PolyShell Entity has closed topology: (i) vertices of polyshell form vertices of triangles, and (ii) every segment of every triangle is shared with exactly one other triangle FACE GDX PolyShell Entity is a topologically open collection of triangles: (i) vertices of polyshell form vertices of triangles, and (ii) every segment of every triangle either is shared with exactly one other triangle or is an edge of face, and (iii) every edge of face belongs to exactly one triangle FACE(S) GDX PolyShell Entity is a collection of FACEs valid/invalid GDX PolyShell Entity meet / does not meet criteria for topologically valid triangulation of face or solid bad/good stitching every non-manifold non-shared segment has / has not a duplicate segment on adjacent face zero-area triangle(s) duplicate segments belong to a triangle overused segment(s) more than two triangles use a segment wrong loop(s) wrong direction of triangle(s)

# Input

## option

(not used)

## opt_level

Level of detail. If opt_level == 1, numerical data is displayed. If opt_level == 2, only verbose description is displayed

## gdx_ps_ptr

GDX PolyShell Entity database pointer

# Return

Usage