Hi Povers

I've got a blob of cylinders (textured), and when I clip either in a seperate
object or inside the blob I get what I'd expect to get if the blob were
hollow which it isn't, I also get this on a seperate object that's unioned
with the blob eg:

#include "kolors.inc"

#version 3.1;

global_settings{   
                assumed_gamma 2.2
               }

camera{
       location <0,2,-5> 
       look_at <0,1,0>
      }   

box{<-50,-2,-50>,<50,-1,50> pigment{Gold} } 

light_source{ <5,10,-50> color rgb 0.7}
light_source{ <-50,100,-12> color rgb 0.7}
light_source{ <50,100,50> color rgb 0.7}

background {MidnightBlue}

#declare acount = 0;

#declare the_angle = 360/5;

#declare the_rotation = 0;

#declare Petals =

blob{
     threshold 0.025

     #while (acount < 6)

       #declare acount = acount+1;    

       cylinder{<0,-1,0>,<0,1,0>, 1, 1.5
                translate z*1
                rotate y*the_rotation
                texture{
                        pigment {Yellow} 
                        finish{ambient 0.1}
                       }                         
               }
              
       #declare the_rotation = the_rotation+the_angle;
    
     #end // End of while.
         
    } // End of Blob.



#declare FlowerWithCenter =
union{
      object{Petals}
      cylinder{<0,-1,0>,<0,1,0>,1 
               texture{
                       pigment{Blue} 
                       finish{ambient 0.1}
                      }
              }

     } // End of union.

#declare FullFlower =
object{FlowerWithCenter
       clipped_by{ cylinder{<0,-0.5,0>,<0,0.5,0>,5}}
      }

object{FullFlower}

// ****************** End of code *****************


I've checked the docs and can't find anything that explains this. 
I'm sure this used to be easier with differences in older versions. 


-- 
Cheers
Steve              email mailto:sjl### [at] ndirectcouk

%HAV-A-NICEDAY Error not enough coffee  0 pps. 

web http://www.ndirect.co.uk/~sjlen/

or  http://start.at/zero-pps

  6:04pm  up 12 days, 20:05,  4 users,  load average: 1.37, 1.33, 1.22

Post a reply to this message

Steve wrote:
> 
> Hi Povers
> 
> I've got a blob of cylinders (textured), and when I clip either in a seperate
> object or inside the blob I get what I'd expect to get if the blob were
> hollow which it isn't, I also get this on a seperate object that's unioned
> with the blob eg:
> 

I don't see a problem here, it works just as I would expect it to.
Making an object 'hollow' has no effect on clipping or CSG, only fog and media.
Clipping always leaves a hole in the object, if that's what you mean. If you
want a surface along the cut, you need to use CSG (intersection or difference) -
just as in the older versions.

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg

Post a reply to this message

On Tue, 09 May 2000 20:40:30 +0300, Margus Ramst wrote:
>Steve wrote:
>> 
>> Hi Povers
>> 
>> I've got a blob of cylinders (textured), and when I clip either in a seperate
>> object or inside the blob I get what I'd expect to get if the blob were
>> hollow which it isn't, I also get this on a seperate object that's unioned
>> with the blob eg:
>> 
>
>I don't see a problem here, it works just as I would expect it to.
>Making an object 'hollow' has no effect on clipping or CSG, only fog and media.
>Clipping always leaves a hole in the object, if that's what you mean. If you
>want a surface along the cut, you need to use CSG (intersection or difference) -
>just as in the older versions.
>

So then I get a black object. So basically I have to texture the object that I'm
taking away from my original construction. 

It'd make life a lot easier if the object being differenced didn't lose it's 
texture, It'd make floors a lot easier, the floor in my current scene was
going to be fairly straight forward, but now that I've discovered this feature
it makes it a lot more complicated. 

-- 
Cheers
Steve              email mailto:sjl### [at] ndirectcouk

%HAV-A-NICEDAY Error not enough coffee  0 pps. 

web http://www.ndirect.co.uk/~sjlen/

or  http://start.at/zero-pps

 11:11pm  up 13 days,  1:12,  4 users,  load average: 1.09, 1.04, 1.00

Post a reply to this message

Steve wrote:
> 
> It'd make life a lot easier if the object being differenced didn't lose it's
> texture,

It does not. But surface that is left at the cut is the surface of the cutting
object, and has the texture of that object.
POV cannot give the cut surface the texture of the object you're cutting,
because in many cases it is impossible to determine what that texture should be.
Consider a CSG merge of two spheres, one red and one green. If you now cut this
object, what colour should the cut surface be?
Generally, it makes sense to leave the component objects untextured and apply
the texture to the whole CSG construct.

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg

Post a reply to this message