Scale

[YoyoBoy]

I don't understand why, when creating a water sim, the scale of the simulation doesn't default to 1.0. I also don't understand why so many tutorials start out with the narrator changing the Max system scale. Shouldn't things always be set to 1.0 unless the look of a different scale is preferred, or does the scale affect the calculation time?

Thanks.

[Svetlin.Nikolov]

Hey,

When you create a brand new Fire/Smoke or Liquid Simulator, the Scene Scale option in the Grid rollout defaults to 1.0.

Perhaps you mean: Why the Scene Scale option is not 1.0 when creating a toolbar preset? This is because I adjust the scale of the presets so that you get the same simulation no matter how large the object you apply the preset to is. For example, applying a candle preset over a sphere 1 cm across would produce the same candle flame simulation as if you applied the preset over a sphere 100 meters across. I chose to do this because people who don't understand scale will not be phased by crazy results they would get if they apply e.g. a large smoke preset which is supposed to behave as if it's several meters tall over a super small object, which would make the fluid erupt straight up out of the emitter with very high speed compared to the emitter because it's so small. And also I wanted to prevent the opposite situation where if you apply e.g. a Candle preset over an emitter several meters tall, it would emit so weakly that it might not even be noticeable and would seem like the simulation is not doing anything.

As for the Max system scale, please link me the tutorial you are interested in. In some of them there could be a reason, for example if you simulate a volcano, you wouldn't want to be working in cm because all numbers would be 5-6 digit long. But I am sure that in some cases a tutorial was made in some units just because the author could make in those units, without any particular reason. However, I insist that all colleagues making tutorials first show their 3ds Max unit setup because if you follow a tutorial with different unit settings that the ones the author used, the results would be different.

The scale could affect the simulation time as well - not always though. Please check this thread from last month where we talk about a similar question: https://forums.chaos.com/forum/phoen...62-scene-scale

Cheers!

[Joelaff]

Ah, very interesting. I had seen the scale start at something other than 1.0 and wondered why. Must have used a template.