I tried to create a sort of crumbled plaster for an object.
Using an intersection of an outer hull and an isosurface.

Unfortunately i run into the problem of having dark areas where i do not 
expect them. The plaster seems to be just a hull and not to be solid.

in past i could get rid of these effects in ISOs by adjusting the 
accuracy & max_gradient settings. But it did not work in this case.

I noticed that the bad effect decreases by lowering the dimensions of 
the contained_by box converging the intersections dimensions.

Does anybody has an idear how to solve this?
It would be great if someone could help, cause i'm somewhat perplexed at 
the moment...

Regards
Joerg


---8<---------8<----------8<---------8<---------8<---------8<----------8<---------8<------
// The Object to be plastered
union{
  box{<-1,0,-1>,<1,1,1>}
  sphere{<0,1,0>,1}
  pigment{color Red}
}


// Funtion for plaster
#declare L10=function{
  pigment{
	bozo
	turbulence 1.25
	scale <4,4,4>
	color_map {
	 [0 rgb 1]
	 [1 rgb 0]
	}
  }
}


// the plaster
#declare B1 = intersection{
  isosurface {
     function { L10(x,y,z).red - 0.5 }
     accuracy     0.00001	// 0.05 the smaller the slower to render
     max_gradient 1.551 		// 2    the smaller the faster to render
     contained_by{box{<-12,-12,-12>,<12,12,12>}}
//    open
  }
  union{
   box{<-1.05,0,-1.05>,<1.05,1.05,1.05>}
   sphere{<0,1,0>,1.05}
  }
  pigment{ color White  }
}

object{B1}
---8<---------8<----------8<---------8<---------8<---------8<----------8<---------8<------

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Joerg <"joerg_[]_schrammel.org"> wrote:
> I tried to create a sort of crumbled plaster for an object.
> Using an intersection of an outer hull and an isosurface.
>
> Unfortunately i run into the problem of having dark areas where i do not
> expect them. The plaster seems to be just a hull and not to be solid.
>
> in past i could get rid of these effects in ISOs by adjusting the
> accuracy & max_gradient settings. But it did not work in this case.
>
> I noticed that the bad effect decreases by lowering the dimensions of
> the contained_by box converging the intersections dimensions.
>
> Does anybody has an idear how to solve this?
> It would be great if someone could help, cause i'm somewhat perplexed at
> the moment...
>
> Regards
> Joerg
>
>
>
---8<---------8<----------8<---------8<---------8<---------8<----------8<---------8<------
> // The Object to be plastered
> union{
>   box{<-1,0,-1>,<1,1,1>}
>   sphere{<0,1,0>,1}
>   pigment{color Red}
> }
>
>
> // Funtion for plaster
> #declare L10=function{
>   pigment{
>  bozo
>  turbulence 1.25
>  scale <4,4,4>
>  color_map {
>   [0 rgb 1]
>   [1 rgb 0]
>  }
>   }
> }
>
>
> // the plaster
> #declare B1 = intersection{
>   isosurface {
>      function { L10(x,y,z).red - 0.5 }
>      accuracy     0.00001 // 0.05 the smaller the slower to render
>      max_gradient 1.551   // 2    the smaller the faster to render
>      contained_by{box{<-12,-12,-12>,<12,12,12>}}
> //    open
>   }
>   union{
>    box{<-1.05,0,-1.05>,<1.05,1.05,1.05>}
>    sphere{<0,1,0>,1.05}
>   }
>   pigment{ color White  }
> }
>
> object{B1}
>
---8<---------8<----------8<---------8<---------8<---------8<----------8<---------8<------


Hi,

I suspect this is because you need to add ALL_INTERSECTIONS to your
isosurface to do CSG.

Also, do you get any warnings about max_gradient?

Sean

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> Hi,
> 
> I suspect this is because you need to add ALL_INTERSECTIONS to your
> isosurface to do CSG.
> 
> Also, do you get any warnings about max_gradient?
> 
> Sean

Hi Sean,

that was it, i added 'all_intersections' and id works :)

Thanks a lot
Joerg

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