Always Use A Scale Reference
When Modeling In 3D
By Neil Blevins
Created On: Aug 27th 2023
How the 3d object you're modeling interacts with the whole
environment is frequently more important than the object itself, and so
getting scale right at the beginning will save everyone a ton of
headache. This short video discusses the advantages of always
considering the scale of the 3D object you're creating, especially when
working with a team, and discuses some tricks to make sure you get the
correct scale from the beginning. Consider it an important reminder,
always start with the correct scale.
You have two choices with this lesson, watch me discuss the issue in
the video below, or read the full text.
So this may seem
like a small thing, but it's a very important thing, and can be easily
forgotten as you're focused on modeling an object in 3d and not yet
worrying about how that object will fit into the larger environment.
But how your objects interacts with the whole is frequently more
important than the object itself, and so getting scale right at the
beginning will save everyone a ton of headache.
What sorts of headaches? Well, beyond having to rescale the object when
it reaches the environment, there's plenty of other ways this can go
sideways. Some material types rely on world space for their coordinate
system, and so scaling your object will mess up your material. If
you're doing simulations such as water or fire, and someone accidently
uses an object that's the wrong size, "scaling" the effect is usually
not as easy as grabbing it and using a Scale tool. And if you rig a
character that's the wrong size, scaling the rig can cause all sorts of
errors, and broken geometry.
So it's far easier to make sure the scale of your object is right in
the first place.
As a somewhat silly but still pertient example, there's this great film
called "This Is Spinal Tap" from the 80s, and there's a scene in the
film that pertains to this, so spolier alert, I'm going to tell you one
of the jokes. The movie is about a ficticious rock band, and in one
scene they want to play a song about "Stone Henge", and they want a
stage prop of one of the pillars, so they draw a diagram. And they
accidently mark it as 18 inches tall instead of 18 feet. So when they
play the concert, instead of this mammoth rock that instills awe and
wonder in the crowd, they get a ridiculous 2 foot rock. The lesson here
is don't be like spinal tap, make sure you have the scale right at the
beginning.
Now it's not totally the artists fault. When you load up almost any
piece of 3d software there's nothing in your scene to tell you the
scale of anything. I mean, there's a grid. But what size is the grid?
What size is a grid square? And is it the small grid square or this
larger grid square that's 1 unit? And to find out the size of a unit,
you have to go find it hidden several menus deep. So 3d software in
general could be a lot better at making scale obvious.
So what I do to solve this is have a 6 foot tall human model in my
scene. Now I'm biased since I am a 6 foot tall human, but it's not the
specific size, the important part is I always have the human in the
scene so I can always turn it on and see the scale of what I'm
modeling. I also have some other scaled models, like a car, or a single
floor of an apartment building. And I use a script I wrote years ago in
3dsmax to quickly pull these assets into my scene, so I can always
check.
At Pixar, we tended to have a flat plane that had a picture of our
Production Designer on it, so when he came to your desk and asked to
see the scale of the object, you'd just load in the flat plane so he
could immediately tell sizes. Again, the important part isn't what you
use as scale reference, the important part is using it.
If you don't have a quick way to load a scale object, another technique
is to always start with one. For example, in 3dsmax, if you make a file
called maxstart.max and place it in the default scenes directory, when
you reset a scene or start 3dsmax from scratch, it will not load a
blank file, but instead it will load your maxstart file, and anything
in it. So make a blank scene, place your human in there, save it as
maxstart, and now everytime you start max you'll have your scale
reference ready. And there are other similar systems for the other
major 3d programs out there.
So please consider using a scale reference when modeling in 3d, it will
save you tons of trouble later on, and will make life easier for the
next person in the pipeline if you're working at a studio.
