“I am driven by the need to produce grand ideas,” Giovanni Battista Piranesi proclaimed,”and I believe that if I was ordered to plan a new universe, I would have the boldness to undertake the task.”

Etcher, architect, designer, and archaeologist, Piranesi (1720-78) certainly was bold in his conceptions, but that apparently did not make him much fun to be with.The English architect Robert Adam, a friend, wrote of him: “His nature is such that it is impossible to learn anything from him, when he speaks he has disparaging ideas, strange and fabulous expressions, from which it is only possible to extract enigmas and nothing clear and precise. In such a way that after a quarter of an hour his company becomes boring.”

While he might have been insufferable in person, Piranesi is never boring on the page. Today he is known primarily as an etcher, one of the greatest of his era and one of the most influential of any time. His influence stems in part from the widespread European interest in Roman antiquity during the 18th and 19th centuries, when local academies collected his prints for use as exemplars for students and others. One such set landed at the Academia de Bellas Artes de San Carlos in Valencia, Spain, and it is from that institution’s holdings that the two dozen sheets currently on view at the Queen Sophia Spanish Institute come.

Broken into two parts, this notably compelling exhibition at once lofts Piranesi’s “grand ideas” and explores his strangeness and some of his enigmas. From the work presented on the first floor – 10 engravings from his most famous series,the “Carceri d’Invenzione” or “Imaginary Prisons,” all from the later edition of 1761 – it would seem Piranesi did plan a universe, in microcosm. It’s not difficult to see why his vision appealed especially to the Romantic artists of later generations.

His prisons are murky worlds devoted to imposing, and impossible, architecture and to sinister tortures. Characterized by vigorous, strong lines that emphasize energy and atmosphere rather than detail, the etchings are sketch-like and, at times, maddening. The scale within them tends to be enormous – almost to the point of sublimity,in the Romantic lexicon – so individual people appear as fuzzy ghosts undergoing obscure torments. The tone, the sense of soaring grandiosity mixed with punishing heaviness, seems more accurately considered than the layouts of the buildings themselves.

Still, it is with their fabulous architecture that the “Imaginary Prisons” entrance: Stairways zigzag endlessly skyward or spiral to nowhere; enormous walls of arches open onto other walls and distant vistas; bridges seem to exist purely for fancy; guard towers look out into infernal, receding depths; massive columns support insubstantial thoroughfares of walkways; what appear to be ceiling vaults turn out to be arches built atop more arches; pulleys drop; wooden drawbridges lift; shadows confuse. They are at once extraordinary and banal. Any one might engage your attention for many long minutes, but it would be hard to prefer one to another, as each seems to be a variation on the one preceding it, another chamber in the edifice.

In the Spanish Institute’s lower-level gallery hang a series of remarkable descriptive etchings, sheets (or volumes) that were sold to travelers on the Grand Tour as mementos. Of these, the vedute (views) of Rome are the most appealing. That the etcher of the “Imaginary Prisons” also made these highly precise scenes is almost shocking: Here the lines are straight and fine, the details minute, and the plan clear.What unites the earlier efforts with the Roman work is the magnificent scale.

Delicate clouds (Piranesi was said to have studied with Tiepolo) hover over a “View of the Piazza di Spagna,” casting solid, expertly rendered shadows on the buildings and dusty piazza. Every architectural line is sharp, every person individualized – although the focus is always on the building, not the person. When you move to a close-up depiction of a building, as in the “View of the Palace Built in Quirinal,” you can feel Piranesi relishing each pucker of the rough-hewn stone, each bit of grillework or sculpted ornament.

That level of detail is even more exceptional when you consider Piranesi’s working methods. According to the catalog, he employed quick sketches with only broad topographical reference points as his guides in creating the etchings.Asked by the artist Hubert Robert how this could be so, he replied, “The drawing is not on paper, but entirely in my head, and you will see this on the copper plate.”

Piranesi’s taste for grand scale and romantic settings found its perfect subject in the Roman antiquities he also depicted. Some, such as the “View of the Bridge and Mausoleum Built by the Emperor Aelius Adrian” – an arched stone bridge leading to a huge, round edifice – have a similar clarity and attention to detail as the vedute. Others, like the “Partial View of the Foundations of the Marcellus Theatre,”while in no way neglecting detail, are so obscure they seem primarily intended for engineers and archaeologists. It is when he fastens on the interaction of nature and buildings – vines and trees growing haphazardly on ruins – that Piranesi’s sense of the antique fascinates most.

Perhaps this is because the slowpaced collision of man and nature in these scenes mirrors Piranesi’s own gifts: wild imagination meeting engineered precision. At the Spanish Institute, the explosions of art resulting from such a clashing sensibility are certainly worth taking in.

Until February 4 (684 Park Avenue at 68th Street, 212-628-0420).