In keeping with my usual pursuit of weathering and erosion, I'm trying to
develop a way of putting cracks into objects. Of course one can always be
cunning with imagemaps and pigments/functions, but sometimes a closeup is
required!

To this end, here's my results so far using (tada!) CSG. I'm still playing with
it, so I'll post more pics as and when.

Bill

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Preview of image 'crack.jpg'

Looks better with a distressed block.

Mind you, I'd be pretty distressed if I had gouges like that in me.

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Attachments:
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Preview of image 'crack.jpg'

Man, your rocks rock! :)

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Bill Pragnell wrote:
> Looks better with a distressed block.
> 
> Mind you, I'd be pretty distressed if I had gouges like that in me.
> 
> 
> ------------------------------------------------------------------------
> 
beautiful.  really got no clue how you did it.  supposing you are 
differencing meshs

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Jim Charter <jrc### [at] msncom> wrote:
> beautiful.  really got no clue how you did it.  supposing you are
> differencing meshs

Correct! I'm using a wedge-sectioned disc perturbed like a heightfield to make
the cuts. It parses and renders very quickly. I'm sure it's also possible with
isosurfaces but I can't immediately see how without vast cunning and
max_gradients. Once I've put it to use and polished it a little I'll probably
upload the macro to the object collection.

:)

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Bill Pragnell nous illumina en ce 2008-10-27 19:42 -->
> Jim Charter <jrc### [at] msncom> wrote:
>> beautiful.  really got no clue how you did it.  supposing you are
>> differencing meshs
> 
> Correct! I'm using a wedge-sectioned disc perturbed like a heightfield to make
> the cuts. It parses and renders very quickly. I'm sure it's also possible with
> isosurfaces but I can't immediately see how without vast cunning and
> max_gradients. Once I've put it to use and polished it a little I'll probably
> upload the macro to the object collection.
> 
> :)
> 
if you want tu use some isosurfaces, it may better to use CSG differences rather 
than try to use a single isosurface.
Like substracting the cracks from the isosurface.
difference{
	isosurface{.....}//main object
	object{Crack1}
	object{Crack2}
	...
	}

-- 
Alain
-------------------------------------------------
Database administrators do it with their relations

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Alain <ele### [at] netscapenet> wrote:
> if you want tu use some isosurfaces, it may better to use CSG differences
> rather than try to use a single isosurface.
> Like substracting the cracks from the isosurface.
> difference{
>  isosurface{.....}//main object
>  object{Crack1}
>  object{Crack2}
>  ...
>  }

Yes, that's exactly how I'm already doing it, but with meshes. I meant I
couldn't see how to make the crack shape with an isosurface, since my cracks
thin to nothing at the edges (I suppose it wouldn't be too difficult to make a
continuous crack).

OTOH, if I used a difference of isosurfaces it wouldn't parse and render in 15
seconds! :)

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If your interesting cracks can work with unions and other of such 
combinations of shapes, then it would be even better than it is already 
now...

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"Sven Littkowski" <Sve### [at] Jamaica-Focuscom> wrote:
> If your interesting cracks can work with unions and other of such
> combinations of shapes, then it would be even better than it is already
> now...

The crack is differenced from the block in the above example. It will work for
any valid parent object, including unions and properly-defined meshes.

(For complex, multitextured unions there will be coincident surface issues, but
this is a problem for any difference{} object - one just has to be careful when
designing unions!)

Bill

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