"scale" and reflection
stretching - also relative to single coordinate directions

#declare RedBall =
sphere{<0,0,0>,1
       texture{ pigment{ color rgb<1,0,0>}
                finish { diffuse 0.9 phong 1}}}
//--------------------- row in z direction ------
object{RedBall scale<1.00,1,1> translate<0,0, 0>}
object{RedBall scale<0.67,1,1> translate<0,0,-3>}
object{RedBall scale<0.33,1,1> translate<0,0,-6>}
object{RedBall scale<1.50,1,1> translate<0,0, 3>}
object{RedBall scale<2.50,1,1> translate<0,0, 6>}
// -------------------- row  in x direction ----
object{RedBall scale<1,4.6,1> translate<-6,0, 0>}
object{RedBall scale<1,2.0,1> translate<-3,0, 0>}
object{RedBall scale<1,0.6,1> translate< 3,0, 0>}
object{RedBall scale<1,0.3,1> translate< 6,0, 0>}
//-----------------------------------------------

scale = changing of the size
general syntax:

scale s

or with different scales in the basic directions:

scale <s_x,s_y,s_z>

this causes a multiplication (enlargement or reduction of the size) of the dimensions of an object in all 3 basic directions. Hereby the x values (width) are multiplicated by s_x, the y values (height) are multiplicated by s_y and the z values (deepth) are multiplicated by s_z.

#declare Wheel =
union{
 // for details see my POV-Ray sample scenes
 }// end of object "Wheel"
//--------------------- 2 Wheels  ------
object{Wheel translate<1,0, 0>}
object{Wheel translate<0,0,-3> scale<-1,1,1>}
//-------------------------------------------

mirrowing at a coordinate plane:

scale <-1,1,1>

this causes an object to be mirrowed at the yz coordinate plane in x direction.

Samples:
"scale 2 global stretching in all directions to the double size.
"scale<1,1,1>" causes nothing, this means that all is shown by 1:1.
"scale<1,0.5,1>" reduces the values in y direction to the half.
"scale<2,1,1>" expands the values in x direction to double width.
"scale<1,1,-1>" mirrows an object at the xy plane in x direction.

Attention:
The step by step application of
rotation, translation and concentrical streching ("scale")
in general is not interchangeable!
The result is not the same if we mix it up - it depends on the sequence on how we apply it! While constructing scene descriptions too shallow this often is a source of many errors with a high potential of frustration!!! .

Hint:
"scale" can also be applied on shapes as well as with other "objects" like textures ("texture"), color patterns ("pigment") and simulated surface deformations ("normal").

Descriptions and Examples for the POV-Ray Raytracer by Friedrich A. Lohmüller

Geometric Transformations with POV-Ray -

"scale" and reflection
stretching - also relative to single coordinate directions

translate | rotate | scale | matrix | shearing | transforms.inc | transform | vector transformations

Descriptions and Examples for the POV-Ray Raytracer by Friedrich A. Lohmüller Geometric Transformations with POV-Ray -

"scale" and reflection stretching - also relative to single coordinate directions

translate | rotate | scale | matrix | shearing | transforms.inc | transform | vector transformations

Descriptions and Examples for the POV-Ray Raytracer by Friedrich A. Lohmüller

Geometric Transformations with POV-Ray -

"scale" and reflection
stretching - also relative to single coordinate directions