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In geology, one of the most interesting sedimentary structures in sands and
sandstones, is cross-bedding. They occur in many sizes and forms, generated
by all kind of processes, from wind to rivers, to sea.
I have built a macro that simulates at least one type of common cross-bedded
sets: the tabular ones.
The image below is an example of the macro output; the macro itself can be
found, again, in p.b.s-f.
Enjoy!!!
Thomas
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Attachments:
Download 'Cross-bedded sandstone_mcr.jpg' (40 KB)
Preview of image 'Cross-bedded sandstone_mcr.jpg'
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I like your works, Thomas.
Would that macro generate each time the same kind of stone, or do you have
some random generators which ensure that the output can be different each
time (by user-selecting a seed for the random generator)? In any way, you
combine observations in nature with your works in the POV-Ray SDL, and that
is a tendency I like very much! Go on, Thomas, do much more of this!
Sven
"Thomas de Groot" <t.d### [at] inter nlnet> schrieb im Newsbeitrag
news:4465d7a6@news.povray.org...
> In geology, one of the most interesting sedimentary structures in sands
> and
> sandstones, is cross-bedding. They occur in many sizes and forms,
> generated
> by all kind of processes, from wind to rivers, to sea.
> I have built a macro that simulates at least one type of common
> cross-bedded
> sets: the tabular ones.
> The image below is an example of the macro output; the macro itself can be
> found, again, in p.b.s-f.
>
> Enjoy!!!
>
> Thomas
>
>
>
Post a reply to this message
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"Sven Littkowski" <sve### [at] jamaica-focuscom> schreef in bericht
news:4465dbb7$1@news.povray.org...
> I like your works, Thomas.
>
Thank you :-)
> Would that macro generate each time the same kind of stone, or do you have
> some random generators which ensure that the output can be different each
> time (by user-selecting a seed for the random generator)? In any way, you
> combine observations in nature with your works in the POV-Ray SDL, and
that
> is a tendency I like very much! Go on, Thomas, do much more of this!
>
That would be possible of course like I did in the Sandstone_mcr, and I even
started to include a random number parameter (still there, but has no
purpose!!). However, in this particular macro, I think that outside control
by the user is better. You can change the parameters from case to case, even
randomize them using RRand(). In fact I did just that in the Sandstone_mcr
for the sandstone blocks at the rear. Here, I would randomize Frequency,
Bedrot1, Bedrot2, and Set. For instance:
#declare Frequency = RRand(5,10,Seed);
#declare Bedrot1 = <0, RRand(-180,180,Seed), -15>;
#declare Bedrot2 = <RRand(0,10,Seed), RRand(-200,200,Seed), 0>;
#declare Set = RRand(0.3,0.7,Seed);
CrossBeddedSandstone()
object {Sphere texture{CrossBeddedSst}}
If you put this in a #while() loop, you will get a different texture each
time.
Hope this answers your question!
Thomas
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