The gap between creator and creation may never have been wider than in the life of author A.A. Milne and his brainchild, Winnie-the-Pooh — a chasm that the movie “Goodbye Christopher Robin” reveals to be a dreary, sad setting for parental detachment and childhood resentment.

Milne (played by Domhnall Gleeson) was once the toast of London society, praised for the light comic verses he wrote for the satirical magazine Punch. But returning from fighting in World War I, he suffered from shell shock and a deep depression — and became determined to write something important about the futility of war. His writer’s block and the complaints of his social-butterfly wife, Daphne (Margot Robbie), make his pursuit of a magnum opus difficult.

Trying to write in their country house, Milne finds himself distracted and unable to write. Instead, he takes long walks with his young son, nicknamed Billy Moon (played at age 8 by Will Tilston), in the woods nearby. Hearing Billy’s stories of his stuffed teddy bear and his other toys, Milne starts writing them down and makes Billy a character in them, under his given name, Christopher Robin.

Milne brings in his friend Ernest Shepard (Stephen Campbell Moore) to draw some illustrations for his poems and short stories. The results — two books of poems, “When We Were Very Young” (1924) and “Now We Are Six” (1927), and two story collections, “Winnie-the-Pooh” (1926) and “The House on Pooh Corner” (1928) — were best-sellers and made Milne a household name around the world.

In Milne’s own household, though, things were not so rosy. Daphne, always distant from her son, allows young Billy to become a media star for a ravenous post-war audience. Billy hates the attention and confides in his nanny, Olive (Kelly Macdonald), but Daphne and Milne are too busy with publicity tours to see their son’s discomfort.

Director Simon Curtis, much as he did with Marilyn Monroe in “My Week With Marilyn,” takes a snippet of English tabloid drama and buffs it into something seemingly precious. He and screenwriters Frank Cottrell Boyce (“The Railway Man,” “24 Hour Party People”) and Simon Vaughan (a TV producer whose credits include “Ripper Street”) draw bright lines between Milne’s wanderings with Billy and the stories in the books, even having Billy echo Milne’s poem “Vespers” in his bedtime prayers.

But Curtis presents the Milne family story, particularly the post-fame horrors to young Billy, in such a drab, predictable way that it blunts the emotional impact. The harshest treatment is heaped on Robbie, playing the thankless role of Billy’s mother, depicted as a shrill, brittle woman who never forgave Christopher Robin for nearly killing her in childbirth. Milne himself is reduced to a dour, morose soul whose only joy — his relationship with his young son — was snuffed out by celebrity, leaving the adult Christopher Robin (Alex Lawther) a jaded, bitter young man.

The message that permeates “Goodbye Christopher Robin” is that characters who have given the world so much joy were the product of and impetus for a lot of pain. Wallowing in that sadness is less pleasant than a heffalump attack, no matter how beautifully the Hundred-Acre Wood is photographed.

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Goodbye Christopher Robin

The story behind the creation of Winnie-the-Pooh is a tedious, unpleasant slog through bad parental behavior.

Where • Area theaters.

When • Opens Friday, Oct. 27.

Rated • PG for thematic elements, some bullying, war images and brief language.

Running time • 107 minutes.