Hunsdale's portrayal of a young woman with Down syndrome who takes control of her life in order to follow her dream of becoming an auto mechanic has been singled out for praise.
The young actor said she is delighted for Niccol and with reactions she has received locally since Poppy was released in May.
Poppy has previously screened at three international film festivals – CinefestOz, Cinemagic Belfast, and LAFemme, where it was a finalist for Best Feature.
Slamdance, now in its 28th year, is a self-described "anti-algorithm festival by filmmakers for filmmakers".
Robin Laing, who co-produced Poppy with Alex Cole-Baker, said Slamdance is known for challenging the status quo and the festival's focus is on discovering overlooked talent and unique voices.
"Poppy was selected from the over 1500 feature films submitted this year," said Laing.
"It will feature in the small [three films] Unstoppable selection."
The Unstoppable section, now in its second year, is programmed by alumni with visible and non-visible disabilities and aims to "eliminate prejudices and gatekeeping that have historically kept disabilities from being represented in the entertainment industry".
Niccol said it was disappointing that she wouldn't be able to attend the festival, which takes place in late January.
"Due to Covid travel restrictions, I won't be packing my snow boots," she said.
"However, it is gratifying to know that Poppy is being well received and understood by international audiences."
Niccol originally wrote Poppy as a short story and reworked it as a film script more than a decade ago. Financial support arrived when the New Zealand Film Commission created the 125 Fund to celebrate the anniversary of women's suffrage.
A grant from the IHC Foundation helped Hunsdale prepare with coaching from Ella Hope-Higginson, and she also gained some authentic motor mechanic experience in Whanganui working with Midtown Motors boss Raj Patel.