IMAGINE A FISHING net for the Loch Ness Monster: three fishing nets, in fact, inside of each other, all shaped like a giant leaky funnel of fabric. The largest is almost 10 feet high and 10 feet wide at the greatest width.

The viewer, standing before this marvel, could find his mind pulled up through the funnel and known out the top. It's difficult to imagine how long toux-Swiderska to make all those circles of sisal. The work hangs at the top by a circle of wire.

Then think of great armsfuls of fluff, gobs of sisal and wool piled on top of each other, clouds sunk from heaven by their own mortality, and weighted down with a stone. This sculpture is by Hanna Jung, who calls it "Two Spaces - the Space for Bare Feet and the Space for a Stone."

As another sculptor, Krystyna Rekosz, put it: "Air and light - these also I try to weave in."

These are two of the remarkable collection of advanced fiber sculptures by 22 Polish textile artists, on exhibit at the Renwick Gallery 17th Street at Pennsylvania Avenue. The exhibit, after it closes Sept. 5, will tour the United States for two years under the auspices of the Smithsonian Travel Exhibition Service. Rita Adrosko, textile curator at the Museum of History and Technology, assembled the show with help from the Polish People's Republic's Ministry of Culture and Art.

The 28 works, most of them huge pieces, are sized as though for the great hall of a Polish castle.This is one time when the Renwick is forced to use effectively its splendid 25-foot ceiling heights. Val Lewton has devised an interesting installation: dramatic, surprising and, in most ways, effective. However, on opening night the crowd, perhaps under the influence of the delicious Polish vodka, couldn't always find their way in and out of the multi-level maze-like settings. One woman was stuck for a time in one of the viewing slits, which she had mistaken for a passageway.

The work will come as a revelation to those people who have only seen the handsome but child-like Polish rugs and tapestries widely sold in this country.. (Locally the Design Store sometimes has sold Polish rugs.) Those who know Polish experimental films and the excellent stylized Polish graphics will be less surprised.

"Spaces" and "Fisnet" are not stand-up-and-cheer works in the show. Wojciech Sadley, hands down, wins the prize for color in her "Violet Structure," a great 500-centimeter outpouring of purple passion cascading down the wall. Izabela Marcjan's "Source II" is a wool tapestry depicting a great cloud weeping smaller clouds. Another Sadley piece of wool and sisal is mostly strings, like moss dripping from a North Florida live oak. Krystyna Czarnocka's "Rosy Stalactite" does indeed look as though it might belong in some vaulted cave. Teresa Muszynska's Jazz Band is five pieces of sisal made of a sort of mad crochet.

Not everything in the shows is abstract and beautiful. There are a few less successful works. Janina Tworek-Pierzgalska's "Spaces," II wool tapestries of feet, hands, a bust and an eye, are in the funky tradition. Barbara Falkowska's "Concert on a Harp" is ghostly hands making appropriate movements.Krystyna Wojtyna-Drouet's "Ludwika and Euzebiusz," of wool, sisal and flax is a shade artsy-craftsy, as is Izabela Marcjan's "Confession" in wool. But then nobody's number comes up all the time. "Shell" by Kaja/Kazimiera/Gidaszewska would be more impressive as a sculpture if I hadn't seen smaller versions made as capes by an accomplished Washington crocheter.

Poland has a thousand-year history of tapestries. Castles, palaces, churches, even peasant huts for centuries have been ornamented by wall hangings. In the early days, the tapestries served a useful purpose, to keep out the drafts whistling through stone walls. The 18th century was a blooming time for tapestries.

At the turn of the century, the art nouveau , or secession as it was known in Vienna and points east, revived the interest in organic dyes and plant forms. In Poland in 1901, according to the catalog (not yet published), the arts and crafts movement, a revival of interest in folk arts, encouraged the formation of artists workshops, the Polish Applied Arts Society and the Society of Krakow Workshops. In these years, the age-old separation between the artist who designed and the craftsman who executed the work was largely eliminated.

In the 1950s the Polish weavers experimented with non-traditional materials and methods, according to Rita Adrosko. In the 1960s the work became more and more monumental and, in some cases, emerged as true fiber sculpture.

Krystyna Kondratiukowa (of the Central Museum of Textiles in Lodz, writing in the catalog, claims that Polish weavers were the inventors of the fiber sculpture art: "Toward the end of the '60s Poland was the birthplace of a new form of expression in weaving - the spatial fabric, first as flat forms, then as three-dimensional - and from here it spread throughout the world." It might be said that the Poles set tapestry free. In the '70s the textile artists work with robes, wires, strings, chords and bands.

The work of five Polish pioneers in the new artists' medium first were noted in the International Biennial of Tapestry, held in 1962 in Lausanne, Switzerland: Magdalena Abakanowicz, Maria Laszkiewicz, Jolanta Owidzka, Wojciech Sadley and Krystyna Wojtyna-Drouet, all of whom are represented in the Renwick show. Early examples of the Polish work was shown in the Museum of Modern Art and the Museum for Contemporary Crafts, both in New York City.

In Washington there are severl craftsworkers who execute handsome textile works, including Ron Goodman, who has taught a number of other Washington artists.

The Polish artists are widely valued. Their work is sold from Japan to the United States. One 71-by-24-feet piece has just been hung in a new government building in the Netherlands. Today's glass and space monumental buildings call for architectural jewelry such as these.

On of the disappointments in the Old Post Office architectural competition, especially to General Services administrator Jay Solomon, himself an art collector, was that none of the artchitect finalists had a concrete idea for the money earmarked for art. A great fiber or textile sculpture by a Washington artist such as Ron Goodman, or one of Sam Gilliam's great unstructured, unfettered canvases, would be magnificient in the 90-foot atrium of the Old Post Office.