Can anyone point me towards creating a decent looking brick arch? I did 
try using a radial bump map and a high frequency. While it looked quite 
funky, it wasn't what I was looking for. Is there a way to take an 
existing texture and bend it?

Post a reply to this message

Shawn wrote:
> 
> Can anyone point me towards creating a decent looking brick arch? I did
> try using a radial bump map and a high frequency. While it looked quite
> funky, it wasn't what I was looking for. Is there a way to take an
> existing texture and bend it?

Real POVer's do is with real 3D objects, lovingly placed by hand, and
textured individually for added realism.

--
Ken Tyler

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Gee your a big help! I was hoping to be lazy!
(now where's me darned trowel....)

Ken wrote:

> 
> Shawn wrote:
> 
>> Can anyone point me towards creating a decent looking brick arch? I did
>> try using a radial bump map and a high frequency. While it looked quite
>> funky, it wasn't what I was looking for. Is there a way to take an
>> existing texture and bend it?
> 
> 
> Real POVer's do is with real 3D objects, lovingly placed by hand, and
> textured individually for added realism.
> 
> --
> Ken Tyler

Post a reply to this message

Shawn wrote:
> 
> Gee your a big help! I was hoping to be lazy!
> (now where's me darned trowel....)

I suppose if you are feeling hopelessly lazy you could search on the
net for a picture of a brick arch and just (shudder!!!) image map it
onto the surface of your choice....but that would be cheating and
you would never have the same satisfaction of doing it like a real
POVer would....and....and....

-- 
Ken Tyler

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Well, ok, I have occasionaly stooped to using an image map or two...(but 
I was forced to by savages! Honest!!) But I was hoping to make something 
worthy of close inspection...at least from 50 paces with an eyepatch?
Ken wrote:

> 
> Shawn wrote:
> 
>> Gee your a big help! I was hoping to be lazy!
>> (now where's me darned trowel....)
> 
> 
> I suppose if you are feeling hopelessly lazy you could search on the
> net for a picture of a brick arch and just (shudder!!!) image map it
> onto the surface of your choice....but that would be cheating and
> you would never have the same satisfaction of doing it like a real
> POVer would....and....and....

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This might or might not help you (probably not):

#declare Th= function{"TH"}
isosurface {
       function { ((z*z+y*y-1.5*1.5)
                  &-(z*z+y*y-1.3*1.3)
                  &abs(x)-0.35)
                  -0.03*GraniteFun(x*3,y*4,z*3)
                  +(0.095-(max(((Th(y,x,z)/4)%0.1),0.095)))*2
                }

        method 2
        //eval
        max_gradient 5

        accuracy 0.001
        contained_by{box {<-0.5,0,-1.6>,<0.5,1.6,1.6>}}

        pigment{....
              }

    }

Remove the GraniteFun-Stuff with whatever displacement you want.

To curve an existing texture declare a pigment-function and use it with some
math as a function-pigment ... if you get what I mean ;-)

Marc-Hendrik


Shawn schrieb in Nachricht <3AE### [at] orthancabca>...
>Can anyone point me towards creating a decent looking brick arch? I did
>try using a radial bump map and a high frequency. While it looked quite
>funky, it wasn't what I was looking for. Is there a way to take an
>existing texture and bend it?
>

Post a reply to this message

Ken <tyl### [at] pacbellnet> wrote:
: Real POVer's do is with real 3D objects, lovingly placed by hand, and
: textured individually for added realism.

  Real POVer's do it with #whiles :)

-- 
#local D=array[6]{11117333955,7382340,3358,3900569407,970,4254934330}
#local I=0;#macro M()<mod(D[I],13)-6,mod(div(D[I],13),8)-3,10>#end
#while(I<6)cylinder{M()#local D[I]=div(D[I],104);M().1
pigment{rgb M()}}#local I=(D[I]>99?I:I+1);#end              /*- Warp -*/

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Shawn <sha### [at] orthancabca> wrote:

> Can anyone point me towards creating a decent looking brick arch? I did 
> try using a radial bump map and a high frequency. While it looked quite 
> funky, it wasn't what I was looking for. Is there a way to take an 
> existing texture and bend it?

If all you want to do is texture it, you can use the following function:

function { funct(sqrt(x*x+y*y), atan2(y,x), z) }

This bends a section of the xy plane around the origin. Funct can be any
pigment function you like. This would allow, for example, you to use a
gradient to create radial stripes, but also allows for stranger things. 
Applied correctly, you should be able to create your arch.

Note that as the distance from the origin gets larger, the texture is going
to scale up.  This shouldn't be too much of a problem for what you're doing.

The other option is to create individual objects.  Using the same function
and a rounded cube iso (or any other iso for that matter), you can create
bricks that are curved.

Geoff

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Ah I can hear the voices of my fore-fathers crying out..."RTFM! RTFM!" I 
think I'll experiment with both suggestions, and well as Marcs. I think 
an isosurface would likely make more sense for what I want to do.
Might even post the result on p.b.images and see if it weathers the 
cannonade. :-)

Thanks!
Shawn

Geoff Wedig wrote:


> If all you want to do is texture it, you can use the following function:
> 
> function { funct(sqrt(x*x+y*y), atan2(y,x), z) }
> 
> This bends a section of the xy plane around the origin. Funct can be any
> pigment function you like. This would allow, for example, you to use a
> gradient to create radial stripes, but also allows for stranger things. 
> Applied correctly, you should be able to create your arch.
> 
> Note that as the distance from the origin gets larger, the texture is going
> to scale up.  This shouldn't be too much of a problem for what you're doing.
> 
> The other option is to create individual objects.  Using the same function
> and a rounded cube iso (or any other iso for that matter), you can create
> bricks that are curved.
> 
> Geoff

Post a reply to this message

Shawn <sha### [at] orthancabca> wrote:

> Ah I can hear the voices of my fore-fathers crying out..."RTFM! RTFM!" I 
> think I'll experiment with both suggestions, and well as Marcs. I think 
> an isosurface would likely make more sense for what I want to do.
> Might even post the result on p.b.images and see if it weathers the 
> cannonade. :-)

Well, this sort of reparameterization isn't in the manuals, really.  It's
something I've kinda worked out by banging my head against it for awhile. 
Reparameterization functions can be really nice *if* you can work out the
equations to transform the basic xyz coordinants where you want, and *if*
you have the processor time to llet it (they can be slow)

Isos are probably the best bet in this case, as they give the greatest
control, but they're also the trickiest to work with.  I've had some luck
with making stone and brick shapes with isos (look at the posts under Door
into Summer and also Into the Abyss.  Both use re-parameterized rounded cube
isos to get the stonework)  I imagine you can get something similar.

Geoff

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Geoff Wedig wrote:

> Well, this sort of reparameterization isn't in the manuals, really.  It's
> something I've kinda worked out by banging my head against it for awhile. 
> Reparameterization functions can be really nice *if* you can work out the
> equations to transform the basic xyz coordinants where you want, and *if*
> you have the processor time to llet it (they can be slow)

Has anyone written anything about functions in Pov? Myself I know 
nothing, but I do have a thick enough skull to take the abuse.

> Isos are probably the best bet in this case, as they give the greatest
> control, but they're also the trickiest to work with.  I've had some luck
> with making stone and brick shapes with isos (look at the posts under Door
> into Summer and also Into the Abyss.  Both use re-parameterized rounded cube
> isos to get the stonework)  I imagine you can get something similar.
> 
> Geoff

Where are these posts? (I only go back to about the 19th due to a 
massive Windows failure, so I may have missed them). Isos do seem tricky 
but also very versatile, The authors name escapes me at the moment, but 
I saw a landscape done with isos....very nice!

Shawn

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Geoff Wedig schrieb in Nachricht <3aeefb25@news.povray.org>...

>Well, this sort of reparameterization isn't in the manuals, really.

The isosurface manual at http://users.skynet.be/smellenbergh/ covers the
substitution of parameters quite good IIRC. Not exactly your though. BTW:
wouldn't it be easier to use the build-in functions TH and R for that (never
tried myself though)?

Marc-Hendrik

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Thanks for the link!

Marc-Hendrik Bremer wrote:


> The isosurface manual at http://users.skynet.be/smellenbergh/ covers the
> substitution of parameters quite good IIRC. 
> Marc-Hendrik

Post a reply to this message

Shawn wrote:
> 
> Can anyone point me towards creating a decent looking brick arch? I did
> try using a radial bump map and a high frequency. While it looked quite
> funky, it wasn't what I was looking for. Is there a way to take an
> existing texture and bend it?

You may find interest at a warp patch I made sometime ago...
see http://pov.grimbert.cjb.net/ 
in the patch section, Warps link.

The transformation are for cylinders, spheres, cones and tori; in both direction
(from bent to straight and vice-versa).
Beware, it's in french, so you may need a translation... And I do not think it
is currently part of any MegaPov (but it also seems that there is something
similar already in a MegaPov)

Post a reply to this message

Shawn <sha### [at] orthancabca> wrote:



> Geoff Wedig wrote:

>> Well, this sort of reparameterization isn't in the manuals, really.  It's
>> something I've kinda worked out by banging my head against it for awhile. 
>> Reparameterization functions can be really nice *if* you can work out the
>> equations to transform the basic xyz coordinants where you want, and *if*
>> you have the processor time to llet it (they can be slow)

> Has anyone written anything about functions in Pov? Myself I know 
> nothing, but I do have a thick enough skull to take the abuse.

>> Isos are probably the best bet in this case, as they give the greatest
>> control, but they're also the trickiest to work with.  I've had some luck
>> with making stone and brick shapes with isos (look at the posts under Door
>> into Summer and also Into the Abyss.  Both use re-parameterized rounded cube
>> isos to get the stonework)  I imagine you can get something similar.
>> 
>> Geoff

> Where are these posts? (I only go back to about the 19th due to a 
> massive Windows failure, so I may have missed them). Isos do seem tricky 
> but also very versatile, The authors name escapes me at the moment, but 
> I saw a landscape done with isos....very nice!

Here are the pics:

http://darwin.cwru.edu/~wedig/summer/summer.png

and

http://darwin.cwru.edu/~wedig/Fortress/abyss010414.jpg
http://darwin.cwru.edu/~wedig/Fortress/abyss010411.jpg

They're using stone, rather than brick, but I'm sure you can see the
versitility of isos from these.

Geoff

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Marc-Hendrik Bremer <Mar### [at] t-onlinede> wrote:


> Geoff Wedig schrieb in Nachricht <3aeefb25@news.povray.org>...

>>Well, this sort of reparameterization isn't in the manuals, really.

> The isosurface manual at http://users.skynet.be/smellenbergh/ covers the
> substitution of parameters quite good IIRC. Not exactly your though. BTW:
> wouldn't it be easier to use the build-in functions TH and R for that (never
> tried myself though)?

Possibly.  Didn't think of it at the time.  And yes, there are some good
reparameterization sites, but their not in the MP manual.  Functions are
only covered briefly there.

Geoff

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From what I can gather, it seems similar to MPovs Uv mapping?  Does it 
deform the object or the texture? Your right, much of that was beyond 
what little French I can speak, I can read enough to get a general idea 
I hope....
Jérôme Grimbert wrote:

> Shawn wrote:
> 
>> Can anyone point me towards creating a decent looking brick arch? I did
>> try using a radial bump map and a high frequency. While it looked quite
>> funky, it wasn't what I was looking for. Is there a way to take an
>> existing texture and bend it?
> 
> 
> You may find interest at a warp patch I made sometime ago...
> see http://pov.grimbert.cjb.net/ 
> in the patch section, Warps link.
> 
> The transformation are for cylinders, spheres, cones and tori; in both direction
> (from bent to straight and vice-versa).
> Beware, it's in french, so you may need a translation... And I do not think it
> is currently part of any MegaPov (but it also seems that there is something
> similar already in a MegaPov)

Post a reply to this message

Thanks!
Yup...definatly interesting. nice work! Actually, stone blocks are more 
in line with the project I'm working on, and will look far better than a 
regular flat texture. Not to mention they aren't so 'linear' and perfect 
looking.
Geoff Wedig wrote:


> Here are the pics:
> 
> http://darwin.cwru.edu/~wedig/summer/summer.png
> 
> and
> 
> http://darwin.cwru.edu/~wedig/Fortress/abyss010414.jpg
> http://darwin.cwru.edu/~wedig/Fortress/abyss010411.jpg
> 
> They're using stone, rather than brick, but I'm sure you can see the
> versitility of isos from these.
> 
> Geoff

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Shawn wrote:
> 
>  From what I can gather, it seems similar to MPovs Uv mapping? 

Not at all. UV mapping is defined by the object and some object do not
have UVmapping 
<Holy war>
That why I think UVmapping is not a good thing for POV.
When the renderer only handle triangles and nurbs, UVmapping 
is probably mandatory. But with object like julia, true CSG,
and isosurface, it's really impossible to have homogeneous 
UVmapping.
<End of Holy war>

> Does it
> deform the object or the texture? 

Only the texture. You still need a normal object.

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Shawn <sha### [at] orthancabca> wrote:

> Thanks!
> Yup...definatly interesting. nice work! Actually, stone blocks are more 
> in line with the project I'm working on, and will look far better than a 
> regular flat texture. Not to mention they aren't so 'linear' and perfect 
> looking.

I'll be releasing my isosurface stone wall macros sometime, but don't hold
your breath.  I've had no time to write docs for them yet.

Geoff

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Holy War?? LOL! I'll grab a helmet then!
OK, next question...how does it work exactly? I was taking a quess on 
what it does, like I mentioned, my French was not up to snuff. (Wonder 
where me ol' verb conjugation book went to?) Actually, what you say 
about uv mapping makes sense to me, I did notice some odd things when I 
brought an old scene file into megapov and added some uv mapping, 
hopefully to better wrap my brick texture (Not the scene I need help 
with) As I'm new to megapov, I likely overlooked something. I had a look 
at the include file for 13 Horror (Author escapes me for the moment) and 
he DID use a radial texture and some csg for the same effect I'm trying 
to get. However, this approach will only work for one row of bricks. If 
you want several rows, you either need to make multiple csgs or come up 
with something else. As has been mentioned, isos would look far better, 
and I will experiment with them for sure, but having an alternate method 
for things not in the center of attention would be handy, and kinder on 
my render time.

Jérôme Grimbert wrote:

> Shawn wrote:
> 
>>  From what I can gather, it seems similar to MPovs Uv mapping? 
> 
> 
> Not at all. UV mapping is defined by the object and some object do not
> have UVmapping 
> <Holy war>
> That why I think UVmapping is not a good thing for POV.
> When the renderer only handle triangles and nurbs, UVmapping 
> is probably mandatory. But with object like julia, true CSG,
> and isosurface, it's really impossible to have homogeneous 
> UVmapping.
> <End of Holy war>
> 
>> Does it
>> deform the object or the texture? 
> 
> 
> Only the texture. You still need a normal object.

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Well, that gives me time to experiment with isos and see what they do 
and how they work. I'm new to megapov; so far I've used photons, and 
like them, but the math behind isos has been a wee bit intimidating. 
However, I've hunted down some tutorials, and I'll see what damage I can 
do. For the main structure I'm planning, they would work nicely. Jerome 
has an idea, that might work well for other stuff as well...so the more 
I've got in my arsenal, the more options I'll have for this scene. :-) 
One day, I may even catch up to Giles!(begin laughing)
*
*
*
*
*
(OK you can stop laughing now.)

Geoff Wedig wrote:

> Shawn <sha### [at] orthancabca> wrote:
> 
> 
>> Thanks!
>> Yup...definatly interesting. nice work! Actually, stone blocks are more 
>> in line with the project I'm working on, and will look far better than a 
>> regular flat texture. Not to mention they aren't so 'linear' and perfect 
>> looking.
> 
> 
> I'll be releasing my isosurface stone wall macros sometime, but don't hold
> your breath.  I've had no time to write docs for them yet.
> 
> Geoff

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Shawn wrote:
> 
> Holy War?? LOL! I'll grab a helmet then!
> OK, next question...how does it work exactly? 

It's just some warps (see the pov definition in the help) : 
before computing the texture, the coordinates of the 
point are somehow massaged. 

Usually, warps are used to repeat a texture, or add some noise.
But the facts are simple: at the entry of any warp, you have a
3D vector (coordinates); at the output, you have a 3D vector.
What happen to the 3D vector inside the warp code is up to the
code.

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