Modeling to real world scale

[sboy]

Hey Maya gurus....

This probably belongs under modeling, but I'll put it here anyway

I've written some scripts to allow the user to set gridlines and subdivisions to whatever units the user wants (miles/yards all the way to cm/mm). This prompted a heated discussion about modeling to scale. I'm in favor of modeling to real-world scale, whereas my friend insists that modeling to real world scale causes problems in Maya. He didn't cite any specific examples, though. For instance, He modelled a 20 cm character that I scaled up to 6ft. I bound it to a rig, and lit the scene. I didn't see any problems, other than that the lights and cameras created were tiny by comparison. No biggie....I just scaled them up. Small price to pay for consistency in model scale, I feel. Does anyone know of any problems with modelling things to real-world scale? I suppose a more accurate question would be...does anyone see any problems with modelling large objects? (because even a "real-world" fly would be about 1cm).

Also, I've encounterd a lot of people who stress leaving the Maya default working unit at "cm", and I keep telling them fine....just model to real world scale. 6ft = 182.88cm . But I often get shrunken models, and I think people just model to whatever feels right, with cm as the default.

Whew....Any thoughts?

[joojaa]

Maya doesent like the basic measurement units changed! Some thing inside maya asume the unit is cm whatever you do. And some like dynamics work in cm scale wathever your scale is so that yu must yourself do the conversion. So watever you do dont go to prefs and set the units to feet or other than cm or you can end up with wierd problems.

Also for some reason maya likes modells small so dont do models in the km scale or you might end up frusttrated.

Now theres no need to not do in realworld scale even tough you dont change the prefs. Just imagine that 1 cm is 1 m and you can do it better. Anyway only relative scale counts... indeed the background doesent even need to be in scale with the character just as long as the camera accounts for this.

Im realy glad i live in europe working with SI-units is so much more comfortable especialy if you do physics. Now if we could only set time to be divisible with 100 instead of 60...

PS. no biggie just scale them up... is a REALY bad idea in some cases. Try avoid doing this, you will loose precicion.

PPS. usualy I modell in real scale or then 1 cm corresponds to 1 m scale (i still think i moddel in real scale just maya unit isnt right because of limitation). But hotever you choose make sure everyone knows the scaleing in advance. Also typing smaller 182.88 when animating can be a bit tedious. and small values form 1 to 10 are ncer to work with most times (because so many other things are constarined in 0 to 1 space making them easier visible in graph editor).

[jeffd]

Yep. I agree with everything Joojaa said. 1cm = 1m. It seems to work best and Maya handles large and small things well if building to that scale.

Also beyond the fact that Maya doesn't like scale changes is the fact that far too many users don't even know how to change this. If you leave the safety of the default centimeters you are taking on a lot of issues when dealing with outside contractors and setting up new employees machines who most likely will be working at the default cm setting. I think it introduces a constant annoyance of scale to a pipeline in which just allowing the default 1cm = 1m approach would work without a hitch.

--JeffD

[sboy]

Thanks Jooja and Jeff!

As far as keeping "cm" the default, can't one just use whatever units they want to build in, and just switch the units to "cm" when they're done? As far as I understand, the actual units used to build with aren't hardcoded anywhere in the objects, only within the scene when it's saved (as verified by saving as .ma).

Therfore the real issue must be in how Maya handles large objects? At what point does Maya act weird? a 182.88 cm human (6 ft)? a 1524 cm building (50 ft)? And in what ways does Maya act weird?

Thanks guys....just trying to understand.