system units inch_drawing units cm

[maxs]

hi,

i have often read the advice to use inches and not cm as system units, cause of sytem stability reasons. also ies shoult work better with units.

how can i manage it that inches are the syst units, but cm are the "drawing" units, as i have to import data from autocad in cm.

i tried it with display unit scale in cm and in system units(inches) "respect syst units in files" unchecked, but the imported cad files dont have the right scale.

thx

[dagor]

system stability?

don`t think inches improve your stability. it doesn`t matter for stability and IES, what unit you use.

only thing your model must be in real word scale.

 

if you go architectural (not interior) rendering it may be more useful and comfortable to use meter or inches or feet instead cm and mm )))

[chiquito]

I work with metric system, not imperial, and never had an issue.

Only thing is to know what you are working with, and export accordingly.

Never heard of anyone complaining because he had an inch and not a meter.

check units set up on both softwares.

[Matt Clementson]

There's a 'rescale' option in the AutoCAD import which will ensure that your imported data comes in at the correct sizes, just make sure you pick the right 'incoming' units from the drop down.

 

The advice about stability is sort of right but it's more to do with MAX's floating point precision. Basically MAX can't store extremely large (or extremely small numbers) that well - unlike a CAD programme which has a much greater level of precision, when the numbers get large you start getting all sorts of geometrical weirdness happening (like straight lines looking wiggly). Most MAX users know to relocate their models to 0,0,0 to avoid this behaviour - what they're doing when they do this is avoid the stored vertex positions getting very large and exceeding the floating point precision.

 

Using inches as your system units does a similar thing - for example 1m stored as mm is going to be 1000 'units' but stored as inches it's only 39.37 'units'. Now multiply this up to a model that's a couple of km across and you can see how using inches as the system units can help minimise those large numbers.

[redzuan3828]

hi,

i have often read the advice to use inches and not cm as system units, cause of sytem stability reasons.

thx

 

I never hear before

But what I'm understand is Every Drawing must have proportion and you can't get proportion without using System units.

I'm using metric. Don't have problem so far:D

[Nic H]

the sooner the world (usa) converts to metric the better

[chiquito]

What I meant by never hearing before: either system you have works fine, you just have to adapt to it, a computer doesnt fail because you use a system rather than other. So I never heard or seen (in my particular case) that for ex, 3d max crashes when you use imperial units and works fine with metric, or viceversa.

Autocad for example can work with multiple systems.

I like converting Imperial to metric, but its a personal choice, proportions queet the same, its maths, so its just the same.

no offense intended to any one.

M.