MAYA scale vs REAL world scale

[13fox]

Heres a question that may seem basic, yet I have never seen addressed:
When you start a project and create, say, a sphere, the scale is 1, 1, 1. What is this measurement and what is the translation in real world (ie inches, feet, etc.)? Keep in mind that the sphere can represent something as small as a marble, or as large as a planet. Imagine you have a marble and a planet in the same scene and you may see what I am getting at when you start to consider things like lighting and texturing.
The reason I am asking is because I am modeling environmental objects like buildings, bridges and landscapes and I want to know what scale I should be using from the start. I normally start in a scale that "feels" right and run into problems when I start texturing and lighting. Going by "feeling" aint gonna cut it anymore. I need some definite answers here... Any help?

Adam

[gmask]

In the preferneces you can set your units to be whatever you like feet inches centimeters.. etc. Some function sin Maya prefer certain setting sthough and the grid and values represent increments of whatever you choose. move something one unit and that is one foot it that's what you set it to.

[empleh]

Out of curiosity, what type of scale related problems do you run into?

ww

[13fox]

problems i run into...
1. putting a light in the scene that may be way too large in relation to the object (minimal adjustments in intensity of said light drastically effecting the object).
2. assigning 2d texture to object. On first assignming texture, it is super huge compared to my object, then I spend an eternity scaling that texture down.

[joojaa]

Well the units have no relevance actualy as long as the maker is avare of their nature so even if you dont use cm you dont need to change anything as long as you are consistent (lights need to be adjusted accordingly offcourse).

its no matter if the camera is 10 cm away on amodell witth cm scale or 10 m apart ina m scale object the render result is the same. go here, under perspective read the topic apparent object size for a good explanation.

[twedzel]

Actually in a production environment, scale is an issue that I wish would be stressed more often. Too often people just start modelling away without really caring about scale. Pretty soon you start importing exporting elements and everything is whacked out and needs re-scaling. Anouther issue is many of Maya's features like light fall off, or dynamics are scale dependant. So it is good to enforce some kind of ground rule for building objects to scale. I have also found that I get display issues if scenes are too large. They just become problematic to work in, so I often work 1/10 scale for most things (one unit based on one meter, makes it really easy to do conversions), or 1/100 the scale for the really really big stuff. As it turns out for some reasons maya's units seem to be ten times larger than some other packages. So you build a guy 1.5 meters tall, he comes into lightwave 15 meters tall. Building 1/10 scale had the side advantage of being compliant with other packages.

[joojaa]

Yeah sure ive ran into this many times. Its a bummer. Also beinga eingeneer by treade i allways keep treck on the scale (altough i usualy dont touch the cm settings inside maya i copensate this with the values), besides without scale its impssible to work with dynamics properly.

[empleh]

I was working on a project in school once where (almost) everyone forgot the scale that we were using. So I was working in cm units which I equated to one foot. others were working at a scale I have yet to figure out, 1 maya unit equals .4 feet. Then others were eyeballed. To make things worse, some students prefs were set so that the default units were inches instead of centimeters and they didn't know. It was a huge mess.

And to make things worse, sometimes the grid display would magicly change so I thought that I was working in the right scale and I wasn't(the grid would display in cm units while the scene units would be in inches). I ended up having to create a sphere with a radius of 1 with all of the settings perfect and then import that into each scene to make sure things were correct by comparison.

AND the character had been rigged at a scale that didn't match anything else. I came close to going to anger management classes after this.

I don't think anything else could have gone wrong.

My background is is architecture so I am a little fanatical about scale, especially on a set or something where the values can be easily adjusted so that they are perfect, or at least exactly what they should be for the design.

I hate you European guys/gals with your simple metric system and it's logic and ease of use. No, wait, I hate the fact that in the US we have teachers and a general public that will not adopt a logical system. It get's so old trying to convert measurments like 4 feet 5 and 7/8 inches inches to anything. Even converting 5/8 of an inch to .625 gets old.

Sorry for the rant/story. Scale is just near and dear to my heart.

ww

[kurtnellis]

The scale you work in has a direct effect such things as dynamics, fur and cloth. All of which have settings to compensate/adjust for the scale you've choosen to work in.

[cyrusthevirus]

Hello,
I am currently wrapping up a digital forensic illustration/virtual anthropology study.

I wish I would have come across this forum sooner, as I could have gotten some good feedback when I came across a similar scale issue.

I had to make precise measurements from reference radiographs in order to calibrate the scale of my model to the real world. In this particular instance I placed my locators at the correct anthropomorphic points and scaled my model(and locators) until the numbers were correct. For this solution I was lucky because I was working directly in proportion to real world reference.

The problem I now have, is that my model is incredibly big. And I am nowing running into some clipping plane issues. I don't know if the "units" function discussed above would have been helpful in my earlier study.

But because I was working off of xrays and I had a "to-scale" measurement from the real world I was able to work around the grid with the aid of the locator tool.

Just thought I'd throw that out there.

low_stress

[mta3d]

amen to the metric system!

[mikleing]

"The problem I now have, is that my model is incredibly big. And I am nowing running into some clipping plane issues."

I've gotten that problem too - the Front/Right/Top windows have problems with near clipping on really big scenes, don't they? Sometimes half your objects disappear, and you wish the near clip could be really low (like -320000) but it won't let you type anything below zero?

Any fixes? -- ie. How do you make sure nothing is clipped from orthagonal windows in a big scene?

-jeremy

[mag]

hang on...

if you put a negative clip value like -32000 in wouldn't that mean that the clipping plane would be way behind the camera so that it wouldn't matter at all anyway and be exactly the same as putting in zero?

the problem is that the orthagonal camera is still a physical camera and when you "zoom" in you're actually moving the camera so if you go really close it's still possible to go past things

[mikleing]

So, how do you make sure you can see all the objects in a front/right/top view on a really big scene, without half of them getting clipped or being considered behind a camera?

I just want a plan view that shows all the objects, looking all the way through the scene -- just the way those windows work by default when viewing smaller scenes.

Zoom just changes the camera's focal length, not its position.

-jeremy

[empleh]

Try translating the orthographic camera away from the scene, by default it is at 100 units I think. You want to translate it to a position where all of the objects are in front of it.

You will also need to change the clipping plane to a depth that includes all of the objects in the scene.

And you will also need to change the "orthographic width" of the camera under the orthographic views section of the camera attribute editor to a value that will include all of the geometry, say 2000 if you have an object that is 1900 units wide.

And you will need to turn the grid off because if your settings are low enough for it the grid will turn solid at a distance and cllip the geometry on the opposite side of the axis.

Good luck,
ww

[mikleing]

Ah thanks! -jeremy

[mag]

oh yeah.. with the orthagonal views it doesn't alter the possition of the camera..

but it does with perspective cameras...

[naveen-raghul]

I've done a tutorial on this topic. It should help you.