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Hi,
Attempting tonight to make a simple lamp shade I failed miserably.
I'm trying to create a lamp shade of the type seen commonly in household
settings. It is cone shaped but has a sine wave pleating as it's suface
feature. I have been able to achieve a sine wave surface through various
means but alas these where all in a flat pattern. Revloving around a
conical circle is not as simple as it sounds and I would appreciate any
tips you may have.
--
Ken Tyler
mailto://tylereng@pacbell.net
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have you concidered using the dome plugin, so far all i have managed to
create is lamp shades!
Rick
Ken <tyl### [at] pacbell net> wrote in message
news:372596DD.494C2FAA@pacbell.net...
> Hi,
>
> Attempting tonight to make a simple lamp shade I failed miserably.
> I'm trying to create a lamp shade of the type seen commonly in household
> settings. It is cone shaped but has a sine wave pleating as it's suface
> feature. I have been able to achieve a sine wave surface through various
> means but alas these where all in a flat pattern. Revloving around a
> conical circle is not as simple as it sounds and I would appreciate any
> tips you may have.
>
> --
> Ken Tyler
>
> mailto://tylereng@pacbell.net
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On Tue, 27 Apr 1999 03:52:13 -0700, Ken <tyl### [at] pacbellnet> wrote:
> Attempting tonight to make a simple lamp shade I failed miserably.
>I'm trying to create a lamp shade of the type seen commonly in household
>settings. It is cone shaped but has a sine wave pleating as it's suface
>feature. I have been able to achieve a sine wave surface through various
>means but alas these where all in a flat pattern. Revloving around a
>conical circle is not as simple as it sounds and I would appreciate any
>tips you may have.
Go get my Jan/Feb IRTC Stills entry (borrow.zip) and make suitable
modifications to the bottle cap object. It's a bunch of patch objects,
so you get the added advantage of double illumination for your lampshade.
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On 27 Apr 1999 09:37:38 -0500, Ron Parker <par### [at] my-dejanewscom> wrote:
>Go get my Jan/Feb IRTC Stills entry (borrow.zip) and make suitable
>modifications to the bottle cap object. It's a bunch of patch objects,
>so you get the added advantage of double illumination for your lampshade.
I just went and grabbed a copy of that file and realized that I never did
get around to documenting it. So, here's some (slight) documentation:
rad this is the average radius at the narrow end of the cone
sl this is the "slope" and should be the difference in average radius
from one end of the cone to the other, divided by 3.
fac The furrows in the bottlecap go from zero amplitude at the narrow
end to fac*3 amplitude at the wide end.
ys ys is the height of the cone, divided by 3. Think "Y-step"
steps steps is twice the number of furrows around the cone. Must be even.
So, here's your cone:
radius at this end is rad, and there are no pleats.
____
/ \
/ \ height is 3*ys
/________\
radius at this end is rad+3*sl +/- fac*3
As for the actual pleated cone, you want to keep the union called "cap_part"
and delete the last two bicubic_patch objects, keeping just the first one.
If you want to make the furrows be of constant depth, you'll have to modify
the part of the code that makes the furrows from
#if ((X=1 | X=2)&(Y>0))
#if ( mod(i,2) )
#local lrad=lrad+fac*(Y-1);
#else
#local lrad=lrad-fac*(Y-1);
#end
#end
to
#if ((X=1 | X=2))
#if ( mod(i,2) )
#local lrad=lrad+fac;
#else
#local lrad=lrad-fac;
#end
#end
and then set fac to the desired amplitude.
Throw away the rest of the include file; you probably don't need the peas or
the test-render version of the cap.
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Ron Parker wrote:
>
> On Tue, 27 Apr 1999 03:52:13 -0700, Ken <tyl### [at] pacbellnet> wrote:
> > Attempting tonight to make a simple lamp shade I failed miserably.
> >I'm trying to create a lamp shade of the type seen commonly in household
> >settings. It is cone shaped but has a sine wave pleating as it's suface
> >feature. I have been able to achieve a sine wave surface through various
> >means but alas these where all in a flat pattern. Revloving around a
> >conical circle is not as simple as it sounds and I would appreciate any
> >tips you may have.
>
> Go get my Jan/Feb IRTC Stills entry (borrow.zip) and make suitable
> modifications to the bottle cap object. It's a bunch of patch objects,
> so you get the added advantage of double illumination for your lampshade.
Thanks Ron I will indeed take a look upon your masterful work.
--
Ken Tyler
mailto://tylereng@pacbell.net
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>Revloving around a
>conical circle is not as simple as it sounds and I would
appreciate any
>tips you may have.
Isn't it possible to define a somewhat rotated 'slab of
shade' and then translating/rotating it around the y-axis?
Something like this:
#declare Slab=box { <0,0,-0.1> , <0.01,1,0.1> rotate
<0,0,20> translate <2,0,0> texture {...} }
#declare Precision=1;
#declare T=0;
#declare SinCount=0;
#while (T<360)
object { Slab translate <sin(SinCount),0,0> rotate y*T}
#declare SinCount=Sincount+pi/(8*Precision);
#declare T=T+1/Precision;
#end
Haven't tested the code, but the idea should work...
Julius
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Hiya Ken,
One workaround is to create your circular sine wave in Illustrator and
bring it into POV as a font ( after converting).
Another workaround would be to create a flat sine wave in the ususal manner
and then use BEND.INC to curve it.
Another workaround might be to create 1 sine wave and then employ rotated
copies of it.
steve
Ken wrote:
> Hi,
>
> Attempting tonight to make a simple lamp shade I failed miserably.
> I'm trying to create a lamp shade of the type seen commonly in household
> settings. It is cone shaped but has a sine wave pleating as it's suface
> feature. I have been able to achieve a sine wave surface through various
> means but alas these where all in a flat pattern. Revloving around a
> conical circle is not as simple as it sounds and I would appreciate any
> tips you may have.
>
> --
> Ken Tyler
>
> mailto://tylereng@pacbell.net
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Another workaround would be to use the dome generator with a
base=hypocycloid or epicycloid
and many sides.
Philippe
>Hiya Ken,
>
>One workaround is to create your circular sine wave in Illustrator and
>bring it into POV as a font ( after converting).
>
>Another workaround would be to create a flat sine wave in the ususal manner
>and then use BEND.INC to curve it.
>
>Another workaround might be to create 1 sine wave and then employ rotated
>copies of it.
>
>steve
>
>
>Ken wrote:
>
>> Hi,
>>
>> Attempting tonight to make a simple lamp shade I failed miserably.
>> I'm trying to create a lamp shade of the type seen commonly in household
>> settings. It is cone shaped but has a sine wave pleating as it's suface
>> feature. I have been able to achieve a sine wave surface through various
>> means but alas these where all in a flat pattern. Revloving around a
>> conical circle is not as simple as it sounds and I would appreciate any
>> tips you may have.
>>
>> --
>> Ken Tyler
>>
>> mailto://tylereng@pacbell.net
>
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Ph Gibone wrote:
>
> Another workaround would be to use the dome generator with a
> base=hypocycloid or epicycloid
> and many sides.
> Philippe
I followed your advice and tried the Dome generater program. After about
15 different tests/renders/rejections I have yet to find a shape that comes
close to what I am hoping for. Perhaps the master could supply me with a
couple of examples of what to enter in the different fields so that I may
learn from his wisdome ?
On a side note:
One undesirable characteristic of the Dome program is that it is producing
a lot of degenerate triangles. You might think about adding a degenerate
triangle testing/removal feature in the program to eliminate these. I had
one file with over 350 degenerate triangles and that is a lot to have to edit
out of the file by hand. Especialy in files that are over 1+ megs in size.
I am not sure how to implement such a routine but there are many here
that I am sure could help you with that. It is a common problem for triangle
generating utilities and the fix I believe is an easy one to add.
On a side-side note:
For some reason I am now mentally calling the Dome program the Domenator.
Resistance is futile. You will be Domenated !
--
Ken Tyler
mailto://tylereng@pacbell.net
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>
> I followed your advice and tried the Dome generater program. After about
>15 different tests/renders/rejections I have yet to find a shape that comes
>close to what I am hoping for. Perhaps the master could supply me with a
>couple of examples of what to enter in the different fields so that I may
>learn from his wisdome ?
I will as soon as tomorrow
>
> On a side note:
> One undesirable characteristic of the Dome program is that it is
producing
>a lot of degenerate triangles. You might think about adding a degenerate
>triangle testing/removal feature in the program to eliminate these. I had
>one file with over 350 degenerate triangles and that is a lot to have to
edit
>out of the file by hand. Especialy in files that are over 1+ megs in size.
>I am not sure how to implement such a routine but there are many here
>that I am sure could help you with that. It is a common problem for
triangle
>generating utilities and the fix I believe is an easy one to add.
>
I'm currently working on a few "inside features" degenerated traiangles
removal is one of them. BTW you get a warning and don't have to remove them
by hand (I never did).
>
> On a side-side note:
> For some reason I am now mentally calling the Dome program the Domenator.
>Resistance is futile. You will be Domenated !
>
I like it, even if I can feel your irony :-)))
Philippe
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