Reactor with mm.

[Woody]

Hi guys,

 

I need some advice on settings for reactor. It seems to me that reactor is set up to work in feet and inches by default. I work in mm so whenever I go to calculate anything it'll bring up an error message with something like "your gravity settings are like Mars you may need to alter them"

 

So what I want to know, is there a quick fix to change reactors default to mm, or if not would someone post examples of settings they're using sucsessfully? The modifyer I am most interested in is the cloth modifier.

 

Cheers!!!

[vadhor]

Woody, you can try to adjust World Scale parameter here:

 

Utility tab (on Command Panel) > reactor > World rollout...

 

From 3ds Max help:

Changing Scale

The Havok physics engine does not care what units of measurement you use when specifying the size of objects or the strength of gravity, it only cares about the numbers - so you could, for instance, work in inches. However, for realistic (or at least predictable!) results, you must be very careful to be consistent. So, for instance, if you are working in meters, then you need to make sure that gravity is set to an appropriate value in meters (if you want Earth-like gravity then use 9.8 m/s2). Otherwise you may find that objects appear to fall far faster or far slower than you expect.

 

Note that, due to CPU floating-point precision, a physics engine will be most accurate when dealing with numbers as close in magnitude to 1 as possible (i.e. values like 10000000 are bad, as are values like 0.0000001). Therefore for real world scenes when creating objects of 1*1*1 size it is more useful to be working in meters or feet than centimeters or kilometers (or inches / miles) in that you will most often be simulating objects larger than sugar cubes and smaller than football fields. It is for this reason that the default values in many physics engines are usually specified in meters.

[Woody]

Cheers Vadhor, It seems to make sense, I'll just have to experiment with it a bit more.