Research for Animation
The first thing to consider for our post-apocalyptic animation, is what caused the extinction level event that transformed the earth in the first place. Our original idea was to have the Yellowstone supereruption be the cause. However, upon reading I’ve found that this would not actually be an extinction level event. The lava flow from the eruption would not make it much further than the Yellowstone national park boundaries – therefore lava wouldn’t be a huge concern. The bigger problem would be the ashfall which would be spread across the United States via wind and air currents. Areas approximately 800 kilometres from Yellowstone would see ash upwards of 1000 inches (25.4 metres). Those living in these regions would likely be killed during the initial event, or soon after from respiratory problems from the ash. Areas outside of this would see diminishing levels of ash from the ashfall and would face more agricultural problems as much of the crop life would die in this environment.
Outside of the US would not really face many problems from earthquakes or ashfall and the only real impact would be climate change. Gases such as sulfur dioxide would be released creating a sulfur aerosol that would absorb sunlight and reflect some back into space. This would cause a short term “climate cooling”. And in turn bring about altered rainfall patterns, along with severe frost, causing more crop losses and famine.
The Yellowstone supereruption idea would only really work if our animation takes place in or around the US to get the desolate look that we intend. Even if the loss of the US and collapse of the rest of the world took place after this due to food shortages and a plummet in population, the rest of the world would be left in a good condition, environmentally speaking, and would in fact see an increase in vegetation.
Map of ash thickness across the US upon Yellowstone volcano erupting.
Tl;dr The eruption itself wouldn’t be a huge problem and only the US would be severely affected. However, we could have the state of the environment caused by volcanic winter which would have similar effects to an asteroid impact or nuclear war, but less intense. (Maybe have the original supervolcano eruption cause earthquakes and other eruptions across the world therefor causing more widespread destruction.
Other ideas for causing apocalypse.
Extreme climate change is the secondary possibility for the cause of the apocalypse in which our story takes place. Due to the adding of carbon dioxide to the atmosphere from human activities. The most extreme outcome of this would be increases in temperature of around 6C. Areas that would experience the worst of this would be poorer countries and would cause mass death - along with famine, and mass migration. Mass poverty, disease and fighting would erupt soon after.
Another candidate for cause of the apocalypse is an asteroid impact. Large asteroid collisions with objects 5km or larger happen around every 20 million years and so it is definitely a possibility. The impact itself would destroy an area around the size of the Netherlands (54,543 km). Areas within this impact zone would be completely decimated leaving a giant, barren crater. The impact cause dust clouds to be shot into the atmosphere – blocking out the sun, causing respiratory problems and having a huge impact on the climate and food etc.
The only other real option is Nuclear war. This idea is somewhat played out at this point though and causes many difficulties in terms of survival. How many nukes were fired and where? As well as the radiation that would be spread by wind and would contaminate most of the food and water supply.
Personally, I don’t think that nuclear war is the event we should use, however I am happy to do in-depth research if that is what we decide to do.
Clothing and weapons
If the disaster, we go for is something like the supereruption or asteroid impact then the people would just wear simple goggles and masks that could be purchased from most hardware stores. The ash is only dangerous if it gets into your body and so a supplied air setup would not be required.
N95 mask which covers the nose and mouth from material getting into the respiratory system. Wouldn’t protect against gases. Eye protection could just be goggles for welding, or building. 
In terms of the rest of their clothing, it would be scarfs, long sleeves, boots and hats/hoods to cover the skin as the ash would cause irritation to the skin.
Something along the lines of:
Skull cap
Goggles
Mask/scarf
Tight neck shirt
Long coat/jacket
Cargo pants
Boots
Gloves (possibly)
The people should be as covered up as possible to protect from particle irritation.
If you wanted to go for a cooler look, gas mask respirators or powered air-purifying respirators could be used) These are masks that cover the entire face and don’t just protect against particulates but gases and chemicals as well. The mask itself covers the entire face and would feature either “canisters” either side of the mouth and charcoal in it to remove chemicals and particles. The other mask would have a tube coming down from the mouth region of the mask which would connect to a small box that purifies the air.
Gas mask respirator to protect against some particulates as well as some chemical gases.
Air purifying respirator which also protects against all particulates and gases. Offers greater protection however is battery powered and so must be charged up to work.
In terms of weapons and other equipment – including vehicles. Moving parts would be a real problem as no matter what scenario we go for, there is going to be a lot of ash, dust or sand (I don’t like sand, its course, rough and irritating, and it gets everywhere)
Whether it is ash, dust or sand, anything that has moving parts would require protection from these particulates otherwise they would soon cease to work. This means that vehicles would have to be completely sealed (perhaps with a type of foam that could cover the seals.
The weapons could be handmade after the disaster and have a look of either something like the Fallout 4 Pipe bolt-action weapon collection.
This is primarily made from wood and what looks like iron. It features screws, springs, tape and some wire. The bolt would have to be pulled back after every shot.
Helpful video for seeing how bolt-action rifles work:
Another mentioned weapon design choice is Roadhogs scrap gun from Overwatch Upon further inspection I don’t think it is a good source of inspiration as it looks like a nerf gun and doesn’t seem like they thought how it actually works. The only part I think we could use are the chains and spikes on the bottom of the weapon which give a good aesthetic but wouldn’t serve any actual purpose.
The other problem with this weapon is when it is in its ultimate form:
As you can see the weapon uses a crank which turns gears that causes the weapon to fire. As I mentioned before moving parts are a real no-no as the particulates would cause this gun to jam up and stop working extremely quickly. The idea of a gun made of scrap that fires scrap is cool, but the design of the gun with all the cogs and wheels would not work.
