[Sidefx-houdini-list] Space filling circles

David Johnson daveinengland at gmail.com
Thu Aug 6 02:02:26 EDT 2009


Another variation would be:
Instead of the last foreach SOP, just add a convert SOP and set the "Convert
to" field to circle. Since they are a little too big, you can use a
primitive SOP to scale them down a bit. Not perfect, but not as squishy as
Andrew's.

Not that there's anything wrong with squishy.

Dave

On Wed, Aug 5, 2009 at 4:07 PM, Andrew D Lyons <tstexture at gmail.com> wrote:

> That's an interesting problem. Not exactly circular - but close:
>
> Drop this in a textport:
> #######################################################
>
> # Automatically generated script: Wednesday August 05, 16:06
> \set noalias = 1
> set saved_path = `execute("oppwf")`
> opcf /obj
>
> # Node circle_cells (Object/geo)
> opadd -n geo circle_cells
> oplocate -x 12.6117 -y 2.05949 circle_cells
> opspareds '    group {  name    "stdswitcher5"  label   "Transform"
> parm
> {           name        "keeppos"           baseparm        joinnext
>  export      none    }
>        parm {      name        "pre_xform"         baseparm        export
>    none    }       parm
> {           name        "xOrd"      baseparm        joinnext        export
>      none    }
>        parm {      name        "rOrd"      baseparm        export      none
>    }       parm {
>  name   "t"         baseparm        export      all     }       parm {
>  name        "r"
> baseparm            export      all     }       parm {      name        "s"
>         baseparm
> export  none    }       parm {      name        "p"         baseparm
>  export      none    }
>        parm {      name        "scale"             baseparm        export
>    none    }       parm {
>  name  "lookatpath"        baseparm        export      none    }       parm
> {
> name    "lookup"            baseparm        export      none    }
> parm {
> name    "pathobjpath"       baseparm        export      none    }
> parm {
> name    "roll"      baseparm        export      none    }       parm {
>  name        "pos"
>            baseparm        export      none    }       parm {      name
>    "uparmtype"
> baseparm            export      none    }       parm {      name
>  "pathorient"
> baseparm            export      none    }       parm {      name
>  "up"        baseparm
> export  none    }       parm {      name        "bank"      baseparm
>  export      none
>        }     }      group {    name    "stdswitcher5_1"        label
> "Material"      parm
> {           name        "shop_materialpath"         baseparm
>  joinnext
> export  none    }       parm {      name        "shop_materialopts"
> baseparm
>  export none    }     }      group {    name    "stdswitcher5_2"
>        label   "Render"        parm {      name        "tdisplay"
>  baseparm
> export  none    }       parm {      name        "display"
> baseparm
> export  none    }       parm {      name        "vm_phantom"        label
>     "Phantom"
>  type   toggle      default     { "0" }             range       { 0 1 }
>         export      none
>            parmtag     { "spare_category" "Render" }   }       parm {
> name    "vm_renderable"             label       "Renderable"        type
>      toggle
> default { "1" }             range       { 0 1 }             export
>  none        parmtag     {
> "spare_category" "Render" }     }       group {             name
>  "folder0"
> label   "Shading"           parm {              name    "categories"
>      label   "Categories"
>                type    string          default { "" }          help    "A
> list of tags which can be
> used to select the object"              range   { 0 1 }
> export  none            parmtag {
> "spare_category" "Shading" }        }       parm {              name
>  "reflectmask"
>                label   "Reflection Mask"               type    oplist
>    default { "*" }                 range   { 0
> 1 }             export  none            parmtag { "oprelative" "/obj" }
>             parmtag {
> "opfilter" "!!OBJ/GEOMETRY!!" }                 parmtag { "spare_category"
> "Shading"
> }               parmtag { "opexpand" "1" }          }       parm {
>      name    "lightmask"
>                label   "Light Mask"            type    oplist
>  default { "*" }                 range   { 0 1 }
>                export  none            parmtag { "oprelative" "/obj" }
>             parmtag { "opfilter"
> "!!OBJ/LIGHT!!" }               parmtag { "spare_category" "Shading" }
>      parmtag {
> "opexpand" "1" }            }       parm {              name
>  "vm_volumefilter"
>                label   "Volume Filter"                 type    string
>    default { "gaussian" }
>                menu    {                   "box"       "Box Filter"
>        "gaussian"  "Gaussian"
> "bartlett"      "Bartlett (triangle)"               "catrom"
>  "Catmull-Rom"
> "hanning"       "Hanning"                   "blackman"  "Blackman"
>          "sinc"      "Sinc
> (sharpening)"           }               range   { 0 1 }
> export  none            parmtag {
> "spare_category" "Shading" }        }       parm {
>                name    "vm_volumefilterwidth"          label   "Volume
> Filter Width"
>                type    float           default { "1.5" }
> range   { 0.001 5 }             export  none
>                parmtag { "spare_category" "Shading" }      }       parm {
>                name    "vm_matte"              label   "Matte shading"
>             type    toggle          default {
> "0" }           range   { 0 1 }                 export  none
>  parmtag { "spare_category"
> "Shading" }         }   }       group {             name        "folder0_1"
> label   "Sampling"          parm {              name    "geo_velocityblur"
>                label   "Geometry Velocity Blur"                type
>  toggle          default { "0" }
>                range   { 0 1 }                 export  none
>  parmtag { "spare_category" "Sampling"
> }           }   }       group {             name        "folder0_2"
> label       "Dicing"
> parm {          name    "vm_shadingquality"             label   "Shading
> Quality"
>                type    float           default { "1" }
> range   { 0 10 }                export  none
>                parmtag { "spare_category" "Dicing" }       }       parm {
>                name    "vm_rayshadingquality"          label   "Ray Shading
> Quality"
>                type    float           default { "1" }
> range   { 0 10 }                export  none
>                parmtag { "spare_category" "Dicing" }       }   }
> group {
> name    "folder0_3"         label       "Geometry"          parm {
>                name    "vm_rmbackface"                 label   "Backface
> Removal (Mantra)"
>                type    toggle          default { "0" }
> range   { 0 1 }                 export  none
>                parmtag { "spare_category" "Geometry" }             }
> parm {
>                name    "shop_geometrypath"             label   "Procedural
> Shader"             type    oppath
>                default { "" }          range   { 0 1 }
> export  none            parmtag {
> "oprelative" "." }              parmtag { "opfilter" "!!SHOP/GEOMETRY!!" }
>                parmtag { "spare_category" "Geometry" }             }
> parm {
>                name    "vm_rendersubd"                 label   "Polygons As
> Subdivision (Mantra)"
>                type    toggle          default { "0" }
> range   { 0 1 }                 export  none
>                parmtag { "spare_category" "Geometry" }             }
> parm {
>                name    "vm_renderpoints"               label   "Render As
> Points (Mantra)"
>                type    toggle          default { "0" }
> range   { 0 1 }                 export  none
>                parmtag { "spare_category" "Geometry" }             }
> parm {
>                name    "vm_metavolume"                 label   "Metaballs
> as Volume"           type    toggle
>                default { "0" }                 range   { 0 1 }
>     export  none            parmtag {
> "spare_category" "Geometry" }       }       parm {              name
>  "vm_coving"
>                label   "Coving"                type    integer
>     default { "1" }                 menu    {
> "0"     "Disable Coving"                    "1" "Coving for
> displacement/sub-d"
> "2"     "Coving for all primitives"             }               range   { 0
> 10 }                export  none
>                parmtag { "spare_category" "Geometry" }             }
> parm {
>                name    "vm_computeN"           label   "Automatically
> Compute Normals"
>                type    toggle          default { "1" }
> range   { 0 1 }                 export  none
>                parmtag { "spare_category" "Geometry" }             }   }
>    }      group
> {       name    "stdswitcher5_3"        label   "Misc"          parm {
>  name        "use_dcolor"
>            baseparm        export      none    }       parm {      name
>    "dcolor"
> baseparm            export      none    }       parm {      name
>  "picking"           baseparm
>            export      none    }       parm {      name        "pickscript"
>        baseparm
> export  none    }       parm {      name        "caching"
> baseparm
> export  none    }       parm {      name        "vport_shadeopen"
> baseparm
> export  none    }       parm {      name        "vport_displayassubdiv"
>         baseparm
>            invisible       export      none    }     }  ' circle_cells
> opset -S on circle_cells
> opparm circle_cells use_dcolor ( off )
> chautoscope circle_cells +tx +ty +tz +rx +ry +rz +sx +sy +sz
> opset -d on -r off -h off -f off -y off -t off -l off -s off -u off -c
> off -e on -b off -x off circle_cells
> opexprlanguage -s hscript circle_cells
> opcf circle_cells
>
> # Node circle1 (Sop/circle)
> opadd -n circle circle1
> oplocate -x 3.41176 -y 0.0882355 circle1
> opparm circle1 type ( poly ) orient ( zx ) rad ( 21 21 ) divs ( 100 )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off circle1
> opexprlanguage -s hscript circle1
>
> # Node triangulate2d1 (Sop/triangulate2d)
> opadd -n triangulate2d triangulate2d1
> oplocate -x 3.41176 -y -1.15882 triangulate2d1
> opparm triangulate2d1 refine ( on ) maxarea ( 2 ) minangle ( 30 )
> maxnewpts ( 19565 ) removeduplicatepoints ( off )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off triangulate2d1
> opexprlanguage -s hscript triangulate2d1
>
> # Node facet1 (Sop/facet)
> opadd -n facet facet1
> oplocate -x 3.50951 -y -3.19412 facet1
> opparm facet1 unique ( on )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off facet1
> opexprlanguage -s hscript facet1
>
> # Node foreach1 (Sop/foreach)
> opadd -n foreach foreach1
> oplocate -x 3.41176 -y -5.02471 foreach1
> chblockbegin
> chadd -t 0 0 foreach1 numrange2
> chkey -t 0 -v 10 -m 0 -a 0 -A 0 -T a  -F 'nprims("../" + opinput(".",
> 0))-1' foreach1/numrange2
> chblockend
> opparm foreach1 fortype ( number ) numrange ( 0 numrange2 1 )
> opset -d on -r on -h off -f off -y off -t off -l off -s off -u off -c
> off -e on -b off foreach1
> opexprlanguage -s hscript foreach1
> opcf foreach1
>
> # Node each1 (Sop/each)
> opadd -n each each1
> oplocate -x 0.6102 -y 4.8513 each1
> chblockbegin
> chadd -t 0 0 each1 attribtol
> chkey -t 0 -v 0.001 -m 0 -a 0 -A 0 -T a  -F 'ch("../attribtol")'
> each1/attribtol
> chadd -t 0 0 each1 attribval1
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F 'stamp("..",
> chs("../forstamp") + "1", 0)' each1/attribval1
> chadd -t 0 0 each1 attribval2
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F 'stamp("..",
> chs("../forstamp") + "2", 0)' each1/attribval2
> chadd -t 0 0 each1 attribval3
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F 'stamp("..",
> chs("../forstamp") + "3", 0)' each1/attribval3
> chadd -t 0 0 each1 attrib
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F
> 'ifs(!!strcmp(chs("../fortype"), "attrib"), "", chs("../attrib"))'
> each1/attrib
> chadd -t 0 0 each1 group
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F
> 'ifs(!!strcmp(chs("../fortype"), "group"), "", stamps("..",
> chs("../forstamp"), ""))' each1/group
> chadd -t 0 0 each1 feedback
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F '!ch("../mergeresults")'
> each1/feedback
> chblockend
> opparm each1 feedback ( feedback ) group ( group ) attrib ( attrib )
> attribval ( attribval1 attribval2 attribval3 ) attribtol ( attribtol )
> forpath ( .. )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off each1
> opexprlanguage -s hscript each1
>
> # Node delete2 (Sop/delete)
> opadd -n delete delete2
> oplocate -x 0.6102 -y 3.89295 delete2
> chblockbegin
> chadd -t 0 0 delete2 rangeend
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F '$N' delete2/rangeend
> chadd -t 0 0 delete2 filter
> chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a  -F 'stamp("../", "FORVALUE", 0)
> == prim("../" + opinput(".", 0), $PR, "__primnum", 0)' delete2/filter
> chblockend
> opparm delete2 negate ( keep ) groupop ( filter ) filter ( filter )
> pattern ( "" )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off delete2
> opexprlanguage -s hscript delete2
>
> # Node fit1 (Sop/fit)
> opadd -n fit fit1
> oplocate -x 0.610753 -y 0.946953 fit1
> opparm fit1 stdswitcher ( 2 2 2 ) method ( interp ) orderu ( 3 )
> orderv ( 3 ) smooth ( 0.343 ) scope ( breakpnt ) dataparmv ( uniform )
> closeu ( wu ) closev ( wv ) corners ( on )
> opset -d on -r on -h off -f off -y off -t off -l off -s off -u off -c
> off -e on -b off fit1
> opexprlanguage -s hscript fit1
>
> # Node circle1 (Sop/circle)
> opadd -n circle circle1
> oplocate -x 3.01075 -y 3.7 circle1
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off circle1
> opexprlanguage -s hscript circle1
>
> # Node resample1 (Sop/resample)
> opadd -n resample resample1
> oplocate -x 0.622517 -y 2.92353 resample1
> opparm resample1 edge ( on ) dolength ( off ) dosegs ( on ) segs ( 2 )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off resample1
> opexprlanguage -s hscript resample1
>
> # Node delete1 (Sop/delete)
> opadd -n delete delete1
> oplocate -x 0.610753 -y 1.85283 delete1
> chblockbegin
> chadd -t 0 0 delete1 rangeend
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F '$N' delete1/rangeend
> chblockend
> opparm delete1 entity ( point ) groupop ( range ) range ( -1 rangeend )
> opset -d off -r off -h off -f off -y off -t on -l off -s off -u off -c
> off -e on -b off delete1
> opexprlanguage -s hscript delete1
> oporder -e each1 delete2 fit1 circle1 resample1 delete1
> opcf ..
>
> # Node __PRIMNUM (Sop/attribcreate)
> opadd -n attribcreate __PRIMNUM
> oplocate -x 3.41176 -y -4.07765 __PRIMNUM
> chblockbegin
> chadd -t 0 0 __PRIMNUM value1
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F '$PR' __PRIMNUM/value1
> chblockend
> opparm __PRIMNUM name ( __primnum ) varname ( __PRIMNUM ) class (
> primitive ) value ( value1 0 0 0 )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off __PRIMNUM
> opexprlanguage -s hscript __PRIMNUM
>
> # Node foreach2 (Sop/foreach)
> opadd -n foreach foreach2
> oplocate -x 3.50951 -y -2.29415 foreach2
> opparm foreach2 fortype ( number ) numrange ( 0 4 1 ) mergeresults ( off )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off foreach2
> opexprlanguage -s hscript foreach2
> opcf foreach2
>
> # Node each1 (Sop/each)
> opadd -n each each1
> oplocate -x 0.6102 -y 4.8513 each1
> chblockbegin
> chadd -t 0 0 each1 attribtol
> chkey -t 0 -v 0.001 -m 0 -a 0 -A 0 -T a  -F 'ch("../attribtol")'
> each1/attribtol
> chadd -t 0 0 each1 attribval1
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F 'stamp("..",
> chs("../forstamp") + "1", 0)' each1/attribval1
> chadd -t 0 0 each1 attribval2
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F 'stamp("..",
> chs("../forstamp") + "2", 0)' each1/attribval2
> chadd -t 0 0 each1 attribval3
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F 'stamp("..",
> chs("../forstamp") + "3", 0)' each1/attribval3
> chadd -t 0 0 each1 attrib
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F
> 'ifs(!!strcmp(chs("../fortype"), "attrib"), "", chs("../attrib"))'
> each1/attrib
> chadd -t 0 0 each1 group
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F
> 'ifs(!!strcmp(chs("../fortype"), "group"), "", stamps("..",
> chs("../forstamp"), ""))' each1/group
> chadd -t 0 0 each1 feedback
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a  -F '!ch("../mergeresults")'
> each1/feedback
> chblockend
> opparm each1 feedback ( feedback ) group ( group ) attrib ( attrib )
> attribval ( attribval1 attribval2 attribval3 ) attribtol ( attribtol )
> forpath ( .. )
> opset -d off -r off -h off -f off -y off -t off -l off -s off -u off
> -c off -e on -b off each1
> opexprlanguage -s hscript each1
>
> # Node divide2 (Sop/divide)
> opadd -n divide divide2
> oplocate -x 0.6102 -y 3.42343 divide2
> opparm divide2 convex ( off ) dual ( on )
> opset -d on -r on -h off -f off -y off -t off -l off -s off -u off -c
> off -e on -b off divide2
> opexprlanguage -s hscript divide2
> oporder -e each1 divide2
> opcf ..
> oporder -e circle1 triangulate2d1 facet1 foreach1 __PRIMNUM foreach2
> opcf ..
>
> opcf /obj
> opcf circle_cells
> opwire -n circle1 -0 triangulate2d1
> opwire -n foreach2 -0 facet1
> opwire -n __PRIMNUM -0 foreach1
> opcf foreach1
> opwire -n -i 0 -0 each1
> opwire -n each1 -0 delete2
> opwire -n delete1 -0 fit1
> opwire -n delete2 -0 resample1
> opwire -n resample1 -0 delete1
> opcf ..
> opwire -n facet1 -0 __PRIMNUM
> opwire -n triangulate2d1 -0 foreach2
> opcf foreach2
> opwire -n -i 0 -0 each1
> opwire -n each1 -0 divide2
> opcf ..
> opcf ..
> opcf $saved_path
>
> ######################################################
>
> 2009/8/5 Doug Struthers <dragonfly at dougstruthers.com>:
> > Thanks for your inputs.
> >
> > Since there do not need to be thousands of them I bet I can iterate on
> them
> > to get a close approximation without taking a long long time to compute.
> >
> > It is intriguing to think that there may be a function with dops that the
> > solution falls out of but I am still a way down the learning curve with
> all
> > the functionality that exists in vops let alone rolling my own.
> >
> > Cheers
> >
> > Doug
> >
> > On Wed, Aug 5, 2009 at 9:09 AM, Gene Dreitser <keyframe at rogers.com>
> wrote:
> >
> >>
> >> Might also be worth it to take a look at the output of the isooffset sop
> >> using the 'tetra-mesh' output type.  Tetra-type set to 'cubes'.
> >>
> >> While it will not pack perfectly, it DOES create a predictable pattern
> of
> >> rows and columns that one might be able to make use, and as an added
> bonus,
> >> it can use ray-intersect to sample the original mesh.
> >>
> >> Best,
> >>
> >> G
> >>
> >>  --
> >> Gene Dreitser
> >> Loki Visual Effects
> >> p: 416.532.5654 // c: 416.803.0682 // www.lokivfx.com
> >>
> >>
> >>
> >> ----- Original Message ----
> >> From: Andy Nicholas <andy at andynicholas.com>
> >> To: sidefx-houdini-list at sidefx.com
> >> Sent: Wednesday, August 5, 2009 12:05:13 PM
> >> Subject: Re: [Sidefx-houdini-list] Space filling circles
> >>
> >> Hi Doug,
> >> Are you asking this because you know of this being done somewhere else?
> I
> >> only ask because I just Googled this (out of my own interest), and
> judging
> >> on how many papers are written on this topic, I'd say that it's a
> >> non-trivial problem to solve.
> >>
> >> The only thing that springs to mind, would be to create an iterative
> >> approach, using the SOP solver or the Feedback SOP (proto_install).
> >>
> >> Note that I haven't tested this, or fully thought it through, but the
> >> following... might... just...  work...
> >>
> >> Start off with a triangular polygon with a random sized disc at each
> >> vertex so that their circumferences touch. From that, take a pair of
> discs
> >> and create another randomly sized one and place it (using simple
> >> trigonometry) so that it touches the first two. Extend the triangle into
> a
> >> four sided polygon with the new point at the center of the new disc.
> >> Repeat the process, but ignoring any discs internal to the polygon.
> >>
> >> I can see this approach breaking down if you ever have a non-convex
> >> polygon, but there are probably some constraints that you could figure
> out
> >> that will prevent this from happening.
> >>
> >> Andy
> >>
> >>
> >>
> >>
> >> > Hi
> >> >
> >> > Can anyone point me to a Houdini method (or other solution) for
> packing
> >> > random sized circles so that they are tightly packed and each
> >> > circumference
> >> > just touches its neighbors?
> >> >
> >> > Thanks
> >> >
> >> > Doug
> >> >
> >> > --
> >> > www.dougstruthers.com
> >> > _______________________________________________
> >> > Sidefx-houdini-list mailing list
> >> > Sidefx-houdini-list at sidefx.com
> >> > https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >> >
> >>
> >>
> >> _______________________________________________
> >> Sidefx-houdini-list mailing list
> >> Sidefx-houdini-list at sidefx.com
> >> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >>
> >> _______________________________________________
> >> Sidefx-houdini-list mailing list
> >> Sidefx-houdini-list at sidefx.com
> >> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >>
> >
> >
> >
> > --
> > www.dougstruthers.com
> > _______________________________________________
> > Sidefx-houdini-list mailing list
> > Sidefx-houdini-list at sidefx.com
> > https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >
>
>
>
> --
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
> _______________________________________________
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