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With that said, we do insist on a level of viability in the assets. This includes time period since pushing past the renaissance gets into the territory of the enlightenment and an era of technological progress not present in our vision of a rough medieval battlescape. The origin of assets should largely remain in Europe because as things come from beyond Europe or cultures that routinely interacted with Europe they start to change the atmosphere of the world. And most importantly, construction. Everything should be able to be plausibly built from materials and using techniques available though the time period.
There's no issue with having some really odd or unique designs, provided that the construction and materials are believable enough. Whether something fits into the world of Chivalry depends more on the execution than on the idea itself.!
Some points to keep in mind:
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