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"B. Gimeno" <nomail@nomail> wrote:
> Thank you both for the notes. You have shown me an unknown path for me.
>The negative part is that a part of my macro will not be limited to the generation
> of rectangular meshes.
No worries - see below:
> Tesellations of hexagonal, triangular symmetry and many
> other motifs can be chosen, which with cylinders, spheres and triangles is
> relatively easy to implement.
I just took a bicubic_patch scene I had and "squished" it into a triangle by
multiplying each row of 4 control points by 1, then 2/3, then 1/3, then 0.
That gives me a triangle-shaped bicubic patch.
That ought to work fine - but I'm thinking that the other control points might
need to be "weighted" to offset the squeezing effect of 4 coincident control
points in the first row, and the narrowing of the patch in rows 2 and 3.
But that's a smoothing issue - build it first, then smooth it. :)
> An old version of my macro is right now in p.b.text-files.
Yes, I finally found that - thank you! :)
It will be interesting to look through what you've done and learn a thing or two
myself.
.... now I'm thinking about making a circular bicubic patch.... :D
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On 11/08/2018 18:16, Bald Eagle wrote:
> .... now I'm thinking about making a circular bicubic patch.... :D
IIRC Moray could make circular (cylindrical) bicubic patches.
It might be worth downloading and having a look at.
--
Regards
Stephen
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Stephen <mca### [at] aolcom> wrote:
> On 11/08/2018 18:16, Bald Eagle wrote:
> > .... now I'm thinking about making a circular bicubic patch.... :D
> IIRC Moray could make circular (cylindrical) bicubic patches.
> It might be worth downloading and having a look at.
I was speaking of circular, as in disc / disk - shaped.
I think I have Moray on my other laptop - I used it to start modeling The Secret
Passage scene. :)
But this is what I came up with - not a perfect circle, which is why I wanted to
pursue the 3x3 patch to have more exactly-specified corner points. Trying to
reverse-interpolate where a point will be based on the control points....
bleh.
Post a reply to this message
Attachments:
Download 'bicubicdisc.png' (224 KB)
Preview of image 'bicubicdisc.png'
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On 11/08/2018 20:42, Bald Eagle wrote:
> Stephen <mca### [at] aolcom> wrote:
>> On 11/08/2018 18:16, Bald Eagle wrote:
>>> .... now I'm thinking about making a circular bicubic patch.... :D
>
>> IIRC Moray could make circular (cylindrical) bicubic patches.
>> It might be worth downloading and having a look at.
>
> I was speaking of circular, as in disc / disk - shaped.
>
Oops!
Discworld - Ringworld, what's the difference? :)
> I think I have Moray on my other laptop - I used it to start modeling The Secret
> Passage scene. :)
>
I remember that. I liked it. :)
> But this is what I came up with - not a perfect circle, which is why I wanted to
> pursue the 3x3 patch to have more exactly-specified corner points.
Not bad at all. :D
> Trying to
> reverse-interpolate where a point will be based on the control points....
> bleh.
>
>
<Walks away whistling.>
--
Regards
Stephen
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On 11/08/2018 22:04, Stephen wrote:
>> But this is what I came up with - not a perfect circle, which is why I
>> wanted to
>> pursue the 3x3 patch to have more exactly-specified corner points.
>
> Not bad at all. :D
Thoughts!
I've found that when working with bezier patches. I have to tune them by
eye.
How about bringing in the outliers in a tad through the radial?
--
Regards
Stephen
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Stephen <mca### [at] aolcom> wrote:
> > Not bad at all. :D
Thanks :) My initial guesses on how to do this turned out to be very close.
Closer than I expected.
> Thoughts!
>
> I've found that when working with bezier patches. I have to tune them by
> eye.
> How about bringing in the outliers in a tad through the radial?
I used a torus to guide me, and had to introduce a number of fudge factors in my
control point matrix. Crap that will look like heiroglyphics to me if I ever
open the file a month from now ;)
Maybe I'll add some comments ... tomorrow. :D
But here it is - as close as I bother making it, and the grid of control points
to show how --- uncircular, and unintuitive that is.
These Coons patches are beginning to look much more interesting...
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Attachments:
Download 'bicubicdisc.png' (185 KB)
Preview of image 'bicubicdisc.png'
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Raising the internal 4 control points gives a Y-paraboloid, and then I inverted
the right two, and got this.
I kinda want to 3D print it and use it as an ice cream spoon.
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Attachments:
Download 'bicubicdisc.png' (195 KB)
Preview of image 'bicubicdisc.png'
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On 12/08/2018 02:36, Bald Eagle wrote:
> Raising the internal 4 control points gives a Y-paraboloid, and then I inverted
> the right two, and got this.
>
> I kinda want to 3D print it and use it as an ice cream spoon.
>
>
>
> Raising the internal 4 control points gives a Y-paraboloid, and then I inverted
> the right two, and got this.
>
> I kinda want to 3D print it and use it as an ice cream spoon.
>
These shapes are so attractive.
I would use it as part of a wind chime, made of crystal glass.
--
Regards
Stephen
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From: Le Forgeron
Subject: Re: challenge: surface connecting cubic_splines
Date: 17 Aug 2018 12:39:04
Message: <5b76fa28@news.povray.org>
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Using a rational bezier patch (well, no need for the rational part here,
all the same weight everywhere)
Rendered with hgpovray38 (for the bezier patch and grid camera)
Post a reply to this message
Attachments:
Download 'hull.pov.txt' (4 KB)
Download 'hull0.png' (357 KB)
Download 'hull5.png' (390 KB)
Preview of image 'hull0.png'
Preview of image 'hull5.png'
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And in a country far far away, someone would have a look at
meshmaker.inc and the Coons macro !
It is there, in all its glory, just waiting to be seen.
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