Hi, I am an architect, who wants something more than what the proprietary modeling softwares offer. And my quest has led me to pursue using BRL CAD. I have little experience in programming, though I am comfortable coding simple scripts.
That said. There is a fundamental question regarding using BRL-CAD and its concepts. Most importantly, the BRL-CAD offers an object hierarchy using a Binary tree, (broadly speaking, a Directed Acyclic Graph) and its algorithms. The primitives, combinations, regions and assemblies are the names we prefer to use in order to point to a specific node of the hierarchy. Primitives, represent leaves of the hierarchy. The two references appended in the mail clarify a lot about the regions and combinations, from the user's perspective. Summarily, I believe that: 1. Combinations are like logical groups, more for the clarity of the user, and primarily intended to store the structure and its implicit transformation matrices. 2. Regions are like physical groups, that can be thought of as an object with one color. Example, to create a wooden table. All the parts of a wooden table can be put together as a region. Along with it there can be subparts of the table that logically grouped into a combination, namely legs, ties (top and bottom), top and so forth. *TODO* I shall try to model and share the example. Please add to my understanding of BRL-CAD wherever necessary. -- (B.V. Raghav) Ph.D. Student, Design Programme Indian Institute of Technology Kanpur Ph: +91-9450988137 Thanks, r References: file:///usr/brlcad/share/doc/html/books/en/BRL-CAD_Tutorial_Series-VolumeIII.html#volIIIorganizing file:///usr/brlcad/share/doc/html/books/en/BRL-CAD_Tutorial_Series-VolumeII.html#boolean_tools -- (B.V. Raghav)
table.g
Description: Binary data
title {Untitled BRL-CAD Database}
units in
put {tbl_tieTop.r} comb region yes tree {u {u {l tieTop_y.s} {l tieTop_y.s100}}
{u {l tieTop_x.s} {l tieTop_x.s100}}}
attr set {tbl_tieTop.r} {region} {R} {region_id} {1001} {material_id} {1} {los}
{100}
put {tieTop_y.s100} arb8 V1 {1168.399999999999863575795
101.5999999999997953636921 679.4499999999997044142219} V2
{1168.399999999999863575795 812.7999999999997271515895
679.4499999999997044142219} V3 {1168.399999999999863575795
812.7999999999997271515895 742.9499999999997044142219} V4
{1168.399999999999863575795 101.5999999999997953636921
742.9499999999997044142219} V5 {1149.34999999999990905053
101.5999999999997953636921 679.4499999999997044142219} V6
{1149.34999999999990905053 812.7999999999997271515895
679.4499999999997044142219} V7 {1149.34999999999990905053
812.7999999999997271515895 742.9499999999997044142219} V8
{1149.34999999999990905053 101.5999999999997953636921
742.9499999999997044142219}
put {tieTop_x.s100} arb8 V1 {1117.59999999999990905053
844.5499999999999545252649 679.4500000000000454747351} V2
{1117.59999999999990905053 863.5999999999999090505298
679.4500000000000454747351} V3 {1117.59999999999990905053
863.5999999999999090505298 742.9500000000000454747351} V4
{1117.59999999999990905053 844.5499999999999545252649
742.9500000000000454747351} V5 {101.5999999999999090505298
844.5499999999999545252649 679.4500000000000454747351} V6
{101.5999999999999090505298 863.5999999999999090505298
679.4500000000000454747351} V7 {101.5999999999999090505298
863.5999999999999090505298 742.9500000000000454747351} V8
{101.5999999999999090505298 844.5499999999999545252649
742.9500000000000454747351}
put {leg_leg.s400} arb8 V1 {1117.59999999999990905053 762 0} V2
{1117.59999999999990905053 812.7999999999999545252649 0} V3
{1117.59999999999990905053 812.7999999999999545252649
742.9499999999999317878974} V4 {1117.59999999999990905053 762
742.9499999999999317878974} V5 {1066.799999999999954525265 762 0} V6
{1066.799999999999954525265 812.7999999999999545252649 0} V7
{1066.799999999999954525265 812.7999999999999545252649
742.9499999999999317878974} V8 {1066.799999999999954525265 762
742.9499999999999317878974}
put {leg_leg.s300} arb8 V1 {50.79999999999999715782906 762 0} V2
{50.79999999999999715782906 812.7999999999999545252649 0} V3
{50.79999999999999715782906 812.7999999999999545252649
742.9499999999999317878974} V4 {50.79999999999999715782906 762
742.9499999999999317878974} V5 {0 762 0} V6 {0 812.7999999999999545252649 0}
V7 {0 812.7999999999999545252649 742.9499999999999317878974} V8 {0 762
742.9499999999999317878974}
put {leg_leg.s200} arb8 V1 {1117.59999999999990905053 0 0} V2
{1117.59999999999990905053 50.79999999999999715782906 0} V3
{1117.59999999999990905053 50.79999999999999715782906
742.9499999999999317878974} V4 {1117.59999999999990905053 0
742.9499999999999317878974} V5 {1066.799999999999954525265 0 0} V6
{1066.799999999999954525265 50.79999999999999715782906 0} V7
{1066.799999999999954525265 50.79999999999999715782906
742.9499999999999317878974} V8 {1066.799999999999954525265 0
742.9499999999999317878974}
put {leg_leg.s100} arb8 V1 {50.79999999999999715782906 0 0} V2
{50.79999999999999715782906 50.79999999999999715782906 0} V3
{50.79999999999999715782906 50.79999999999999715782906
742.9499999999999317878974} V4 {50.79999999999999715782906 0
742.9499999999999317878974} V5 {0 0 0} V6 {0 50.79999999999999715782906 0}
V7 {0 50.79999999999999715782906 742.9499999999999317878974} V8 {0 0
742.9499999999999317878974}
put {leg_leg.c103} comb region no tree {l leg_leg.s400 {1 0 0 50.8 0 1 0 50.8
0 0 1 0 0 0 0 1}}
put {leg_leg.c102} comb region no tree {l leg_leg.s300 {1 0 0 50.8 0 1 0 50.8
0 0 1 0 0 0 0 1}}
put {leg_leg.c101} comb region no tree {l leg_leg.s200 {1 0 0 50.8 0 1 0 50.8
0 0 1 0 0 0 0 1}}
put {leg_leg.c100} comb region no tree {l leg_leg.s100 {1 0 0 50.8 0 1 0 50.8
0 0 1 0 0 0 0 1}}
put {tieTop_y.s} arb8 V1 {69.84999999999995168309397 101.5999999999997953636921
679.4499999999997044142219} V2 {69.84999999999995168309397
812.7999999999997271515895 679.4499999999997044142219} V3
{69.84999999999995168309397 812.7999999999997271515895
742.9499999999997044142219} V4 {69.84999999999995168309397
101.5999999999997953636921 742.9499999999997044142219} V5
{50.79999999999995452526491 101.5999999999997953636921
679.4499999999997044142219} V6 {50.79999999999995452526491
812.7999999999997271515895 679.4499999999997044142219} V7
{50.79999999999995452526491 812.7999999999997271515895
742.9499999999997044142219} V8 {50.79999999999995452526491
101.5999999999997953636921 742.9499999999997044142219}
put {tieTop_x.s} arb8 V1 {1117.59999999999990905053 50.79999999999995452526491
679.4500000000000454747351} V2 {1117.59999999999990905053
69.84999999999995168309397 679.4500000000000454747351} V3
{1117.59999999999990905053 69.84999999999995168309397
742.9500000000000454747351} V4 {1117.59999999999990905053
50.79999999999995452526491 742.9500000000000454747351} V5
{101.5999999999999090505298 50.79999999999995452526491
679.4500000000000454747351} V6 {101.5999999999999090505298
69.84999999999995168309397 679.4500000000000454747351} V7
{101.5999999999999090505298 69.84999999999995168309397
742.9500000000000454747351} V8 {101.5999999999999090505298
50.79999999999995452526491 742.9500000000000454747351}
put {tbl_top.s} arb8 V1 {1219.19999999999981810106 0 0} V2
{1219.19999999999981810106 914.3999999999999772626325 0} V3
{1219.19999999999981810106 914.3999999999999772626325
19.04999999999999715782906} V4 {1219.19999999999981810106 0
19.04999999999999715782906} V5 {0 0 0} V6 {0 914.3999999999999772626325 0}
V7 {0 914.3999999999999772626325 19.04999999999999715782906} V8 {0 0
19.04999999999999715782906}
put {tbl_top.r} comb region yes tree {l tbl_top.s {1 0 0 0 0 1 0 0 0 0 1
742.95 0 0 0 1}}
attr set {tbl_top.r} {region} {R} {region_id} {1000} {material_id} {1} {los}
{100}
put {tbl_leg.r} comb region yes tree {u {u {l leg_leg.c100} {l leg_leg.c101}}
{u {l leg_leg.c102} {l leg_leg.c103}}}
attr set {tbl_leg.r} {region} {R} {region_id} {1002} {material_id} {1} {los}
{100}
put {all.g} comb region no tree {u {u {l tbl_leg.r} {l tbl_tieTop.r}} {l
tbl_top.r}}
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