Question: Kim Ji-hoon starred in Natalie, which was the first Korean film of what type?

Context paragraphs:
The Tower (2012 South Korean film): The Tower (; "Tower") is a 2012 South Korean disaster thriller film about a fire that breaks out in a luxury skyscraper in central Seoul on Christmas Eve.  The film is directed by Kim Ji-hoon, and stars Sol Kyung-gu, Kim Sang-kyung and Son Ye-jin in the lead roles.  It was released in theaters on Christmas Day, December 25, 2012.

Goddess of Marriage: Goddess of Marriage () is a 2013 South Korean romantic comedy-drama series starring Nam Sang-mi, Kim Ji-hoon, Lee Sang-woo, Lee Tae-ran, Kim Jung-tae, Jo Min-su, Kwon Hae-hyo, Jang Young-nam and Jang Hyun-sung.  It premiered on SBS on June 29, 2013, and ended on November 3, 2013, airing every Saturday and Sunday at 21:50 for 36 episodes.

I Want to See Your Parents' Face: I Want to See Your Parents' Face is an upcoming South Korean film directed by Kim Ji-hoon and based on a play by Seigo Hitazawa.

Kim Ji-hoon (actor born 1981): Kim Ji-hoon (born May 9, 1981) is a South Korean actor.  He is best known for his romantic comedies on television such as "The Golden Age of Daughters-in-Law" (2007), "Love Marriage" (also known as "Matchmaker's Lover", 2008), "Stars Falling from the Sky" (also known as "Wish Upon a Star", 2010), and "Flower Boys Next Door" (2012).  In 2010, he also appeared in the film "Natalie", and cable mystery series "Joseon X-Files".

Natalie (film): Natalie (Hangul: 나탈리 ; RR: "Natalri "; MR: "Nat‘alli " ) is a 2010 South Korean romance mystery erotic film co-written, directed and produced by Ju Kyung-jung.  It was the first Korean 3D film.

Joseon X-Files: Joseon X-Files () is a 2010 South Korean television series starring Kim Ji-hoon, Im Jung-eun, Kim Kap-soo and Jo Hee-bong.  It aired on tvN from August 20 to October 29, 2010 on Fridays at 24:00 for 12 episodes.

Kim Ji-hoon (actor, born 2000): Kim Ji-hoon (born 9 January 2000) is a South Korean actor.  He began his career as a child actor, and more recently starred in the 2013 teen soap opera "Melody of Love".

Kim Ji-hoon: Kim Ji-hoon or Kim Ji-hun () is a Korean name consisting of the family name Kim and the masculine given name Ji-hoon, and may refer to:

Kim Ji-hoon (director): Kim Ji-hoon (born 1971), also spelled Kim Ji-hun, is a South Korean film director.

Kim Ji-hoon (sailor): Kim Ji-hoon (born June 27, 1985) is a South Korean sailor.  He and Kim Chang-ju placed 19th in the men's 470 event at the 2016 Summer Olympics.

Supporting paragraphs: Kim Ji-hoon (actor born 1981) Natalie (film)
Answer: the first Korean 3D film