Modem technology and science have produced a wealth of new materials and new ways of using old materials．For the artist this means wider opportunities．There is no doubt that the limitations of materials and nature of tools both restrict and shape a man's work．Observe how the development of plastics and light metals along with new methods of welding has changed the direction of sculpture．Transparent plastic materials allow one to look through an object, to see its various sides superimposed on each other (as in Cubism or in an X-ray)．Today, welding is as prevalent as casting was in the past．This new method encourages open designs, where surrounding and intervening space becomes as important as form．itself.
More ambiguous than other scientific inventions familiar to modem artists, but no less influential, are the psychoytic studies of Freud and his followers, discoveries that have infiltrated recent art, especially Surrealism．The Surrealists, in their struggle to escape the monotony and frustrations of everyday life, claimed that dreams were the only hope．Turning to the irrational world of their unconscious, they banished all time barriers and moral judgments to combine disconnected dream experiences from the past, present and intervening psychological states．The Surrealists were concerned with overlapping emotions more than with overlapping forms．Their paintings often become segmented capsules of associative experiences．For them, obsessive and often unrelated images replaced the direct emotional message of expressionism．They did not need to smash paint and canvas; they went beyond this to smash the whole continuity of logical thought.
There is little doubt that contemporary art has taken much from contemporary life．In a period when science has made revolutionary strides, artists in their studios have not been unaware of scientists in their laboratories．But this has rarely been a one-way street．Painters and sculptors, though admittedly influenced by modern science, have also molded and changed our world．If breakup has been a vital part of their expression, it has not always been a symbol of destruction．Quite the contrary: it has been used to examine more fully, to penetrate more deeply, to yze more thoroughly, to enlarge, isolate and make more familiar certain aspects of life that earlier we were apt to neglect．In addition, it sometimes provides rich multiple experiences so organized as not merely to reflect our world, but in fact to interpret it.
The welding techniques______.