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In such objects as bicubic patches, what do the u & v stand for in u_steps
and v_steps? Or in the example given in the documentation,
(http://www.povray.org/documentation/view/52/) in the uv_vectors and
uv_mapping?
I presume they stand for the same thing in all instances?
--LibraryMan
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LibraryMan <mrm### [at] att net> wrote:
> In such objects as bicubic patches, what do the u & v stand for in u_steps
> and v_steps? Or in the example given in the documentation,
> (http://www.povray.org/documentation/view/52/) in the uv_vectors and
> uv_mapping?
They don't stand for anything. They are names of coordinates in the
same way as x, y and z are.
--
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}// - Warp -
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Program ended abnormally on 4/1/03 5:24 PM, Due to a catastrophic
LibraryMan error:
> Warp wrote:
>
>> They don't stand for anything. They are names of coordinates in the
>>same way as x, y and z are.
>>
>
>
> Is there a 'w'?
>
In theory, yes. In POV, no. "u" and "v" are used to give directions *on* a
surface. For example, in uv_mapping, they are used to align a texture with the
surface of the object; "w" would be perpendicular to the surface, so it does not
play a part in the alignment of the texture. In a FEA package, on the other
hand, "w" could be used internally to compute the density variation inside an
individual element along a third dimension.
--
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/* flabreque */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/* @ */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/* videotron.ca */}camera{orthographic location<6,1.25,-6>look_at a }
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