I have a vehicular game with physics based movement. If I were to scale all assets and levels down to say 1/10th scale, and then scale all values driving the linear components of the physics by the same amount, could I expect the physics and overall movement to be near-enough identical? I’m using async physics if that makes any kind of difference, though I’m guessing not.
i assume its the mass not the scale that really matters? so you could just override that
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Hey there @Perfect_Human_Interface! As Auran mentioned, most of what matters is the mass and you can determine that however you’d like. However, a small caveat is that the smaller (in true scale) things get in Unreal, the worse they perform in various ways. For example, discrete physics stop being accurate when really small or certain lighting mechanisms like Lumen or raytracing will struggle with objects once they get too small and sometimes will be entirely occluded. It’s usually recommended to keep things somewhat above sub-unit scale. However if you’re trying to get a “toy” look, try adjusting the focal length of the camera first and see if it gets the point across.
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Oh I forgot about mass, since I do not use it. All my physics use Accel Change.
That’s good to know, although it seems to be true in the other direction as well. My game is an airplane game and it’s approximately real-scale, with 1UU = 1cm. You move at very high speeds and as such the world and the objects within end up being quite large. I have encountered a number of issues working in Unreal that seem to be a result of the large scales: Landscape tools aren’t sized appropriately, modelling tools become unusable when working with large enough objects, weird artifacts on simple materials placed on large objects, and I’m unsure the effects of lighting at such large scales in terms of both the results and the performance.
So my current scale is large enough that it would probably not get into “dangerously small” territory if scaled down. But my question is mainly about whether I can expect the game to feel and play the same after doing so. I don’t know the math behind the physics, whether just dividing the forces by X results in precisely 1/X the speeds and accelerations and distances travelled. And I don’t know how consistent UE’s physics are in that regard. It would be a significant amount of work to change everything so I was hoping to get an idea whether or not it made sense to before making any attempt.