Displacemnt Map

1 )

i have a simple cube to experiment with this technic

If you want very fine details you need to subdivide a lot
which means lots of memory and much longer time to render!

2 ) Pictures

 F5 you select  Image 

 Then what do you do to put this color image on the cube ?

 and what about the Black and gray image  in the book
 how do you work with this type of image ?


 is it possible to put the image on one face of the cube only ?

Tanks & Salutations

I’m not entirely sure what it is that you mean, but if you want to know how to use a displacement map, yes you need to have a fair few subdivisions to make displacement noticeable.
To apply the displacement (texture)map on a cube, in the ‘Map input’ click the cube mapping button and in the ‘Map to tab’ click on ‘Disp’ and move the slider below to however much you want the displacement to affect your object.
To put the map on just one face, check out the multiple materials at

http://mediawiki.blender.org/index.php/Manual/PartIII/Multiple_Materials

I hope this helps.

but how do you apply the image to all faces or one face

color or black & White image

and for picture do you need to subdivide a lot or not ?

Salutations

Just use a material with the image and assign the material to only one face or the faces you want.