IritTrimSrf2Polygons

Section: C Library Functions (3)
Updated: IRIT Version 6.0
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NAME

IritTrimSrf2Polygons()

SYNOPSIS

prsr_lib/ip_cnvrt.c:454

IPPolygonStruct *IritTrimSrf2Polygons(TrimSrfStruct *TrimSrf,
                                      int FourPerFlat,
                                      RealType FineNess,
                                      int ComputeUV,
                                      int Optimal)

DESCRIPTION

Routine to approximate a single trimmed surface by polygons. FourPerFlat cause four triangles from each flat patch, two otherwise. FineNess is an estimate on number of polygons for each side of mesh if Optimal = 0, otherwise a FineNess curvature control on the maximal distance between the surface and its polygonal approximation. Optimal is a two digits number where the units hold the subdivision strategy and the tens the termination criteria.

PARAMETERS:

TrimSrf: To approximate using polygons.

FourPerFlat: If TRUE, four triangle per flat surface patch are created, otherwise only two.

FineNess: Fineness control on polygonal approximation. The larger this number is the finer the approximation becomes. 10 is a good compromise when Optimal is FALSE.

ComputeUV: Do we want UV parameter values with the vertices of the triangles?

Optimal: If FALSE (0) then parametric space of TrimSrf is sampled

uniformely. Otherwise: If the tenths digit of Optimal is equal to 1. Subdivide the surface alternatively in U and V. 2. Subdivide the surface in the direction that minimizes the error of the approximation If the units digit of Optimal is equal to 0. No real error analysis. The fastest way. 1. Use curvature surface analysis to decide where to subdivide. Much slower than 0. 2. Use a bilinear surface fit to estimate error. Somewhat slower than 0. 3. Combine 1 and 2 for a bilinar fit error measure with curvature analysis. Very slow.

FUNCTION RETURN VALUE

IPPolygonStruct *: Resulting polygons that approximates TrimSrf.

ORIGIN

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Time: 07:27:18 GMT, October 17, 2022