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>Has anyone ever made, or thought of making a library of mesh objects to
>approximate some of POV-Ray's primitives?
>As I understand it, I can declare a mesh object once, and then just translate
>instances of it, which doesn't take up any, or very much more memory.
>I'd be interested in learning how, and helping to generate a library of macros
>for parameterized mesh objects, so that one could simply add
>Does this sound like a good idea? Worthwhile?
It is a good idea, and I have done some things in line with that.
But the crux here is not to replace a single sphere with a single
mesh.
The idea is to create a _set of multiple spheres_ as _a single mesh_
and break the whole scene into such complex meshes.
The sphere is a bad example because it is too complex for demo purposes.
But imagine that you are making a large office building that is fitted
out with the same kind of furniture on every floor. (I dunno, a hotel?)
For simplicity we assume that the there is only one type of chair and
one type of table, conviniently made up of boxes... :p
So then we create the object using this type of call:
#local bW = 1;
#local bH = 1;
#local bT = 1;
#local bX0 = 0;
#local bY0 = 0;
#local bZ0 = 0;
#include "blah blah search path blah \ Mesh.tch"
and in mesh.tch the code is:
____________________________________________________________________________________________
#local trn = <bX0, bY0, bZ0>;
#local BtmP1 = < bW/2, 0, bT/2>+trn;
#local BtmP2 = <-bW/2, 0, bT/2>+trn;
#local BtmP3 = <-bW/2, 0, -bT/2>+trn;
#local BtmP4 = < bW/2, 0, -bT/2>+trn;
#local TopP1 = < bW/2, bH, bT/2>+trn;
#local TopP2 = <-bW/2, bH, bT/2>+trn;
#local TopP3 = <-bW/2, bH, -bT/2>+trn;
#local TopP4 = < bW/2, bH, -bT/2>+trn;
// btm
triangle{ BtmP1, BtmP2, BtmP3 }
triangle{ BtmP1, BtmP4, BtmP3 }
// top
triangle{ TopP1, TopP2, TopP3 }
triangle{ TopP1, TopP4, TopP3 }
// front
triangle{ BtmP1, BtmP2, TopP2 }
triangle{ TopP1, TopP2, BtmP1 }
// back
triangle{ BtmP3, BtmP4, TopP4 }
triangle{ TopP3, TopP4, BtmP3 }
// left
triangle{ BtmP2, BtmP3, TopP3 }
triangle{ TopP2, TopP3, BtmP2 }
// right
triangle{ BtmP1, BtmP4, TopP4 }
triangle{ TopP1, TopP4, BtmP1 }
____________________________________________________________________________________________
the chair is created by something like:
#local ChairObj =
mesh{
// leg 01
#local bW = .1;
#local bH = 1;
#local bT = .1;
#local bX0 = 0.5;
#local bY0 = 0;
#local bZ0 = 0.5;
#include "blah blah search path blah \ Mesh.tch"
// leg 02
#local bW = .1;
#local bH = 1;
#local bT = .1;
#local bX0 = -0.5;
#local bY0 = 0;
#local bZ0 = 0.5;
#include "blah blah search path blah \ Mesh.tch"
blah blah two more legs
// seat
#local bW = 1;
#local bH = .1;
#local bT = 1;
#local bX0 = 0;
#local bY0 = 1;
#local bZ0 = 0;
#include "blah blah search path blah \ Mesh.tch"
// back support
#local bW = .5;
#local bH = .5;
#local bT = .1;
#local bX0 = 0.5;
#local bY0 = 1;
#local bZ0 = 0;
#include "blah blah search path blah \ Mesh.tch"
} // end mesh
So if the chair consists of 4 legs, 1 seat and one back support, you have have
saved 5 objects and the scene will now have x/6 objects.
The table is done in the same way, and one could probably make table group with
chairs and a table as single mesh.
I have also made a box that is rotatable:
(you cannot use rotate or translate on the triangles inside the mesh, at least
not when I wrote the code)
// LOAD ONCE
#include "blah blah\MeshPntTrn.Inc"
// BOX PARAM
#local bW = 1;
#local bH = 4;
#local bT = 1;
#local Init_Trn = <0, 0, 0>;
// ANGLE PARAM
#local aX = 60;
#local aY = 0;
#local aZ = 0;
// TRN PARAM
#local Place_Trn = <0, 0, 0>;
#include "blah blah\ROT_TRN.tch"
___________________________________________________________________________________________________________
MeshPntTrn.Inc
#macro ROT_X(p, aP)
#if(p.y = 0)
#if (p.z=0)
#local a0 = 0;
#else
#local a0 = atan2d(p.z, p.y);
#end
#else
#local a0 = atan2d(p.z, p.y);
#end
#local p = <p.x, sqrt(p.y*p.y + p.z*p.z)*cos(-(a0+aP)*pi/180),
sqrt(p.y*p.y + p.z*p.z)*sin((a0+aP)*pi/180)>;
//#local p = <sqrt(p.y*p.y + p.z*p.z)*cos(-(a0+aP)*pi/180), p.y,
sqrt(p.y*p.y + p.z*p.z)*sin(-(a0+aP)*pi/180)>;
#end
#macro ROT_Y(p, aP)
#if(p.x = 0)
#if (p.z=0)
#local a0 = 0;
#else
#local a0 = atan2d(p.z, p.x);
#end
#else
#local a0 = atan2d(p.z, p.x);
#end
#local p = <sqrt(p.x*p.x + p.z*p.z)*cos(-(a0+aP)*pi/180), p.y,
sqrt(p.x*p.x + p.z*p.z)*sin(-(a0+aP)*pi/180)>;
#end
#macro ROT_Z(p, aP)
#if(p.x = 0)
#if (p.y=0)
#local a0 = 0;
#else
#local a0 = atan2d(p.y, p.x);
#end
#else
#local a0 = atan2d(p.y, p.x);
#end
#local p = <sqrt(p.x*p.x + p.y*p.y)*cos(-(a0+aP)*pi/180), sqrt(p.x*p.x +
p.y*p.y)*sin((a0+aP)*pi/180), p.z>;
#end
#macro TRN(p, PT)
#local p = <p.x+PT.x, p.y+PT.y, p.z+PT.z>;
#end
___________________________________________________________________________________________________________
ROT_TRN.tch
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// ASSIGN VALUES, implementation
#local BtmP1 = < bW/2, 0, bT/2> + Init_Trn;
#local BtmP2 = <-bW/2, 0, bT/2> + Init_Trn;
#local BtmP3 = <-bW/2, 0, -bT/2> + Init_Trn;
#local BtmP4 = < bW/2, 0, -bT/2> + Init_Trn;
#local TopP1 = < bW/2, bH, bT/2> + Init_Trn;
#local TopP2 = <-bW/2, bH, bT/2> + Init_Trn;
#local TopP3 = <-bW/2, bH, -bT/2> + Init_Trn;
#local TopP4 = < bW/2, bH, -bT/2> + Init_Trn;
ROT_X(BtmP1, aX);
ROT_X(BtmP2, aX);
ROT_X(BtmP3, aX);
ROT_X(BtmP4, aX);
ROT_X(TopP1, aX);
ROT_X(TopP2, aX);
ROT_X(TopP3, aX);
ROT_X(TopP4, aX);
ROT_Y(BtmP1, aY);
ROT_Y(BtmP2, aY);
ROT_Y(BtmP3, aY);
ROT_Y(BtmP4, aY);
ROT_Y(TopP1, aY);
ROT_Y(TopP2, aY);
ROT_Y(TopP3, aY);
ROT_Y(TopP4, aY);
ROT_Z(BtmP1, aZ);
ROT_Z(BtmP2, aZ);
ROT_Z(BtmP3, aZ);
ROT_Z(BtmP4, aZ);
ROT_Z(TopP1, aZ);
ROT_Z(TopP2, aZ);
ROT_Z(TopP3, aZ);
ROT_Z(TopP4, aZ);
#local BtmP1 = BtmP1 + Place_Trn;
#local BtmP2 = BtmP2 + Place_Trn;
#local BtmP3 = BtmP3 + Place_Trn;
#local BtmP4 = BtmP4 + Place_Trn;
#local TopP1 = TopP1 + Place_Trn;
#local TopP2 = TopP2 + Place_Trn;
#local TopP3 = TopP3 + Place_Trn;
#local TopP4 = TopP4 + Place_Trn;
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// DRAW BOX, implementation
// btm
triangle{ BtmP1, BtmP2, BtmP3 }
triangle{ BtmP1, BtmP4, BtmP3 }
// top
triangle{ TopP1, TopP2, TopP3 }
triangle{ TopP1, TopP4, TopP3 }
// front
triangle{ BtmP1, BtmP2, TopP2 }
triangle{ TopP1, TopP2, BtmP1 }
// back
triangle{ BtmP3, BtmP4, TopP4 }
triangle{ TopP3, TopP4, BtmP3 }
// left
triangle{ BtmP2, BtmP3, TopP3 }
triangle{ TopP2, TopP3, BtmP2 }
// right
triangle{ BtmP1, BtmP4, TopP4 }
triangle{ TopP1, TopP4, BtmP1 }
____________________________________________________________________________________________
Sorry for the "meshy" post but I am in a hurry... I will have more time tomorrow
But yes it is a good idea and it has saved me lots of trouble. :)
Best wishes! /A
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