[povray virgin warning!]

Hi,
I'm trying to transform objects in some basic CSG (see code below), but I
notice that the transformation only applies to the finished CSG object.
I realize I can do the arc transformation inside the arc macro, and pass a
zillion parameters for rotating, translating, etc, but IMO that's not how
it should be. You can't foresee all possible sequential transformations.
Any help will be greatly appreciated!
Steven


-------------- code start ----------------

#macro arc (H, W, L)
union {
    cylinder { <-L / 2, W, 0>, < L / 2, W, 0>, W / 2 }
    box { <-L / 2, -.001, -W / 2>, <L / 2, W , W / 2> }
    }
#end

difference {
  box { <-50, 0, -50>, <50, 0, 50> }
  // subtract following
  arc (50, 40, 120)                     // along the x-axis
  arc (50, 40, 120) rotate y * 90       // along the z-axis

  pigment { Gray85 }
}
---------------- code end ----------------

Post a reply to this message

"stevenvh" <nomail@nomail> wrote:
> #macro arc (H, W, L)
> union {
>     cylinder { <-L / 2, W, 0>, < L / 2, W, 0>, W / 2 }
>     box { <-L / 2, -.001, -W / 2>, <L / 2, W , W / 2> }
>     }
> #end
>
> difference {
>   box { <-50, 0, -50>, <50, 0, 50> }
>   // subtract following
>   arc (50, 40, 120)                     // along the x-axis
>   arc (50, 40, 120) rotate y * 90       // along the z-axis
>
>   pigment { Gray85 }
> }
> ---------------- code end ----------------

Assuming I know what you want to do try invoking your macro within an
object{} block (or even union{} block):

object{arc (50, 40, 120) rotate y * 90}

Then any transforms are isolated from the rest of the object and you don't
need to pass any variables.


-tgq

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That's it exactly. Thanks, Trevor.
(and quick reply as well!)

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