Venus and Mars (as far as I remember) are drawn to Earth’s orbit to become habitable. They flourish with the Earth but all of the sudden the three planets started to fight for domination. The result of that war is that planets are turned to dust, and the rest of human kind started a journey through the Universe. The beginning of the movie is animated. Not sure about the rest of it. Which movie is that?
“Battle for Terra” (2007), also known as “Terra”
https://www.imdb.com/title/tt0858486/
Detailed plot summary on Wikipedia here:
https://en.wikipedia.org/wiki/Battle_for_Terra
Quote from the above Wikipedia page:
“Giddy tells Mala that centuries beforehand, both Mars and Venus were terraformed by humans and colonized due to the consumption of natural resources. But 200 years later, the two planets demanded independence from Earth, which the Earth government refused to grant to them due to the high demand of resources from the two colonies. This dispute eventually escalated into a violent interplanetary war that rendered all three planets uninhabitable. The remnants of the human race traveled for several generations in the Ark across space looking for a new home, before they arrived at Terra, and gave it its name.”
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